Appendix-CD-2A - CHEOPS Generic Documentation

Appendix – CD-2A
CHEOPS Generic Documentation

Model Documentation
For:

Project XXX

CHEOPS™ Model

September 2002

Developed by:

© Copyright 2003 Devine Tarbell & Associates, Inc.

NOTE:

This is a draft example document, which has had all of the graphics and figures
containing detailed project information removed. The purpose of this document to
provide background information regarding the model input and operation.

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TABLE OF CONTENTS
Hydroelectric Project .................................................................................... 1
CHEOPS™ Model......................................................................................................................... 1
1.0 PURPOSE AND DEFINITION_____________________________............................................1
1.1 PURPOSE....................................................................................................................................1
1.1.1 BASIC HARDWARE REQUIREMENTS .........................................................................................3
1.1.2 BASIC SOFTWARE REQUIREMENTS...........................................................................................3
1.2 TERMS AND DEFINITIONS .....................................................................................................3
2.0 MODEL ARCHITECTURE________________________________ ..........................................7
2.1 CONCEPT OVERVIEW ....................................................................................................................7
2.1.1 SCENARIOS...............................................................................................................................7
2.1.2 SYSTEM SETTINGS....................................................................................................................8
2.1.2.1 Load Shape Condition............................................................................................................... 8
2.1.2.2 Capacity Prices Condition......................................................................................................... 8
2.1.2.3 Regulation Volume Condition................................................................................................... 9
2.1.2.4 Reserve Volume Condition.......................................................................................................9
2.1.2.5 Spinning Capacity Condition....................................................................................................9
2.1.2.6 Gerle Gate Automation Condition..............................................Error! Bookmark not defined.
2.1.2.7 Carry-Over Elevations Condition.............................................................................................. 9
2.1.2.8 Forecast Set-Up Condition.......................................................................................................10
2.1.3 PHYSICAL SETTINGS...............................................................................................................10
2.1.3.1 Reservoir Storage Curve Condition..........................................................................................11
2.1.3.2 Reservoir Area Curve Condition..............................................................................................11
2.1.3.3 Daily Evaporation Condition....................................................................................................11
2.1.3.4 Tailwater Curve Condition.......................................................................................................11
2.1.3.5 Spillway Curve Condition........................................................................................................12
2.1.3.6 Ramp Rating Curve .................................................................................................................12
2.1.3.7 Tunnel/Gate Curve...................................................................................................................12
2.1.3.8 Plant Options Condition...........................................................................................................12
2.1.3.8.1 Non-Generating Plant.........................................................................................................13
2.1.3.8.2 Strictly Peaking Plant..........................................................................................................13
2.1.3.8.3 Peaking with Ramp Rates Plant ..........................................................................................13
2.1.3.8.4 Re-Regulating Plant............................................................................................................14
2.1.3.8.5 Fill and Spill.......................................................................................................................14
2.1.3.8.6 Pure Run-of-River ..............................................................................................................14
2.1.3.8.7 Diversion Plant...................................................................................................................14
2.1.4 OPERATION SETTINGS............................................................................................................14
2.1.4.1 Flood Elevation Condition.......................................................................................................15
2.1.4.2 Target Elevations Condition.....................................................................................................15
2.1.4.3 Minimum Elevations Condition...............................................................................................15
2.1.4.4 Water Withdrawal Condition...................................................................................................16
2.1.4.5 Fluctuation Limits Condition...................................................................................................16
2.1.4.6 Fluctuation Rates Condition.....................................................................................................17
2.1.4.7 Minimum Instantaneous Flow Condition .................................................................................17
2.1.4.8 Minimum Daily Flow Condition..............................................................................................17
2.1.4.9 Bypass Flow Condition............................................................................................................18
2.1.4.10 Ramping Rates Condition........................................................................................................18
2.1.4.11 Flashboards Condition.............................................................................................................18
2.1.5 GENERATION SETTINGS..........................................................................................................19
2.1.5.1 Turbine Generator Condition...................................................................................................19
2.1.5.1.1 Headloss Component..........................................................................................................20
2.1.5.1.2 Turbine Component............................................................................................................20
2.1.5.1.3 Generator Component.........................................................................................................21
2.1.5.1.4 Gate Leakage Component...................................................................................................21
2.1.5.2 Maintenance Schedule Condition.............................................................................................21
2.1.5.3 Minimum Flow Unit Condition................................................................................................22

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2.2 UNIT DISPATCH ..........................................................................................................................22
2.3 DAILY TIME STEP LOGIC SEQUENCE...........................................................................................23
2.3.1 RETRIEVAL OF CONSTRAINT DATA ........................................................................................23
2.3.2 SUM OF INFLOWS ...................................................................................................................23
2.3.3 DAILY DISCHARGE CALCULATION.........................................................................................24
2.4 15-MINUTE TIME STEP................................................................................................................24
2.4.1 DISCHARGE PRIORITIES BASED ON LOADSHAPE......................................................................24
2.4.2 CONSTRAINT CHECKING ........................................................................................................25
2.5 MODEL LOGIC FLOW CHART......................................................................................................25
3.0 USER’S MANUAL________________________________________........................................28
3.1 MAIN MODEL INTERFACE...........................................................................................................28
3.1.1 SAVING DATA INTERFACE......................................................................................................28
3.1.1.1 Retrieving Data........................................................................................................................28
3.1.1.2 Saving Data.............................................................................................................................29
3.1.2 INDIVIDUAL PLANT CONDITION INTERFACE...........................................................................29
3.1.2.1 Physical Conditions .................................................................................................................30
3.1.2.1.1 Reservoir Storage Curve, Reservoir Area Curve, Daily Evaporation, Tailwater Curve,
Spillway Curve, Ramp Rating Curve.......................................................................................................30
3.1.2.1.2 Plant Options......................................................................................................................30
3.1.2.2 Operational Conditions............................................................................................................31
3.1.2.2.1 Flood Elevations, Target Elevations, Minimum Elevations .................................................31
3.1.2.2.2 Water Withdrawals.............................................................................................................31
3.1.2.2.3 Fluctuation Limits and Fluctuation Rates............................................................................32
3.1.2.2.4 Min Instantaneous Flow and Min Daily Average Flow .......................................................32
3.1.2.2.5 Bypass Flow.......................................................................................................................34
3.1.2.2.6 Ramping Rates ...................................................................................................................35
3.1.2.2.7 Flashboards ........................................................................................................................35
3.1.2.3 Generation Conditions.............................................................................................................35
3.1.2.3.1 Plant Set-Up.......................................................................................................................36
3.1.2.3.1.1 Headloss.......................................................................................................................36
3.1.2.3.1.2 Turbines.......................................................................................................................36
3.1.2.3.1.3 Generators....................................................................................................................37
3.1.2.3.2 Maintenance Schedule........................................................................................................38
3.1.2.3.3 Minimum Flow Unit...........................................................................................................38
3.1.2.4 Plant Settings...........................................................................................................................39
3.1.2.4.1 Physical Setting..................................................................................................................39
3.1.2.4.2 Operational Settings............................................................................................................40
3.1.2.4.3 Generation Settings.............................................................................................................40
3.1.3 SYSTEM SETTING INTERFACE.................................................................................................40
3.1.3.1 Load Shape..............................................................................................................................41
3.1.3.2 Capacity Prices........................................................................................................................42
3.1.3.3 Regulation Volume..................................................................................................................42
3.1.3.4 Reserve Volume ......................................................................................................................42
3.1.3.5 Spinning Reserve.....................................................................................................................43
3.1.4 SET UP AND RUN SCENARIO INTERFACES ..............................................................................43
3.1.5 VIEW OUTPUT INTERFACE......................................................................................................45
3.2 RULE CURVE OUTPUT VIEWER INTERFACE.................................................................................45
3.2.1 HAZE CHART DESCRIPTION....................................................................................................46
3.2.2 ANNUAL DETAILS PLOT .........................................................................................................46
3.2.3 DURATION CURVE DESCRIPTION............................................................................................47
3.3 DETAILED OUTPUT VIEWER INTERFACE.....................................................................................47
3.4 ENERGY OUTPUT VIEWER INTERFACE ........................................................................................48
3.4.1 VIEW MONTHLY RESULTS......................................................................................................49
3.4.2 VIEW ANNUAL BENEFITS.......................................................................................................49

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1.0 PURPOSE AND DEFINITION_____________________________
1.1 PURPOSE
DTA created the CHEOPS™ hydropower system simulation model as an accurate and
easy-to-use tool for evaluating a wide range of physical changes (e.g.; turbine upgrades)
and operational constraints (e.g.; minimum flows) associated with relicensing or
upgrading single and multiple-development hydro systems. One of the many strengths of
the CHEOPS™ model is the degree of customization each individual model contains.
The model is tailored to meet the demands of the particular system being modeled. The
unique CHEOPS™ program architecture provides a platform for investigating each
project specific feature under scrutiny.

CHEOPS™ is designed for long-term analysis of the effects of operational and physical
changes made to the modeled hydro-system. CHEOPS™ is calibrated on a daily,
monthly and yearly basis, with hourly verification of model-produced, detailed schedule.
For production use the CHEOPS™ model output should be reviewed on the monthly and
annual basis where trends reflecting generation changes based on changes to a system’s
physical and operational constraints, can be monitored. The detailed schedule should be
used primarily as a “check” that the model is scheduling the system in a reasonably
representative manner.

A clear understanding of the model’s design focus can help to avoid any misuse of the
CHEOPS™ model. DTA did not create CHEOPS™ as a real-time scheduling model. As
was stated earlier, CHEOPS™ should be used for long-term analyses. It was not
designed to answer questions like “How should we schedule the system over the 24 – 196
hours?” rather a more appropriate question might be “How much will it cost annually, on
average, if we operate with an additional 200 cfs bypass flow at one of the plants in the
system?”

SYSTEM REQUIREMENTS

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Computer requirements, and the subsequent run times, vary according to the complexity
of the model, principally involving the number of plants in the system. The CHEOPS™
model considers water control structure in the system (dam, diversion, gate structure,
etc.) as a “plant.” As with any mathematically and computationally intensive software,
performance is directly related to the processor speed and amount of available memory
(RAM) of the computer performing the calculations. In addition to the speed of the
processor and quantity of RAM memory, the speed of the hard drive is important because
the CHEOPS™ model outputs data in the form of text files. Writing these text files can
be a time consuming task.

The CHEOPS™ model is developed on computers running 650 MHz Pentium III
processors with over 128 MB of RAM memory. These computers can run one year of
the XXX Project model in approximately 3 to 5 minutes, depending on the complexity
of the scenario and the hydrologic year that was chosen. As the system becomes
increasingly constrained both by operational and hydrologic constraints, the model runs
can increase as the model must check and perform more calculations. DTA believes that
95% of the XXX Project scenarios will have single year runs times in the range of 3 to
4 minutes on computers comparable to the development machines.

The user needs a hard drive with a minimum of approximately 1 Gigabyte of open space.
The CHEOPS™ model uses a fairly small amount of space, less than 50 MB, but the
detailed (15-minute) output can be quite large. The XXX Project system has 2 plants; a
detailed output file requires approximately 3.2 MB of space for each plant for each year.
Multiplied out, 11 plants for a period of record run of 23 years results in over 800 MB of
output files. It is extremely rare that the user would run a period of record run storing the
detailed output, but the user may so desire.

In addition to hardware the user needs to have a copy of Microsoft® Excel for Microsoft®
Office 97 to view the summarized CHEOPS™ output data (Excel 2000 also appears to
work, although it has not been tested as thoroughly as Excel for Office 97).

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1.1.1 Basic Hardware Requirements
• IBM Pentium PC or compatible computer
• 128 Megabytes of Random Access Memory (RAM)
• CD-ROM Drive
• VGA color monitor with 800 x 600 resolution (1024 x 768 is highly recommended)
• Microsoft® Windows® compatible, non-postscript printer
• Microsoft® compatible mouse
• Hard disk space requirements vary depending on amount of detailed results stored.
Approximately 3.5 MB are used per plant for each year of detailed output.
1.1.2 Basic Software Requirements
• Microsoft® Windows® 95, or Windows® 98. (Windows NT and Windows 2000
should also work, but have not been tested extensively)
• Microsoft® Excel for Microsoft® Office 97

1.2 TERMS AND DEFINITIONS
Accretion Flows – The incremental flow between two plants. Also known as local
inflow.
Acre-ft – A measure of volume – 1 acre of water 1 foot deep (43,560 cubic feet).
Bypass Flows – Bypass flows are those that are required 24 hours a day and are not
released through a powerhouse.
Bypass Flow Destination – Ultimate destination for bypass flows, either returning at a
downstream plant, or leaving the system altogether.
cfs – A measure of flow – 1 cubic feet per second
CHEOPS™ – Computer Hydro-Electric Operations and Planning Software
Component – A named data set that is a building block for a condition.
Condition – The main building block of a scenario, containing the data used by the
model to simulate the system. At this time the only condition that is defined by
components is ‘Turbine Generator’.
DTA – Devine Tarbell & Associates, Inc.

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Discharge – Water released by a plant
Dispatch – A portion of CHEOPS™ that determines, given performance data for a
specific plant, the most efficient way to divide flow among a plant’s units.
Flood Elevation – The reservoir elevation at which the plant spills.
Gate Leakage – The amount of water that leaks through the wicket gates for each unit
when the gates are closed.
Generator – The device that converts rotating mechanical energy into electric potential.
Gross Head – The difference between the headwater elevation and the tailwater
elevation.
Head – A vertical height of water that represents potential energy.
Headloss – The amount of head that is lost (to friction, etc.) between the headwater
(reservoir/forebay/intake) and the tailwater.
Inflow – The flow water entering a plant’s reservoir.
Level – Reservoir surface elevation
Level Fluctuation – The change in reservoir surface elevation.
Level Fluctuation Limits – A constraint specifying the number of feet allowed between
the maximum elevation and minimum elevation achieved each day.
Level Fluctuation Rates – A constraint specifying the maximum allowable rate of
elevation change for the reservoir.
Load Shapes – The daily schedule of power pricing and the hour durations of each price.
Local Inflow – The incremental inflow between two plants (also known as Accretion
Flows).
Mainstream Plant – A plant located on the main stream that runs through the system.
Not a plant on a side or tributary stream.
Maintenance – The scheduled removal of a unit from service for repair or upgrade.
Minimum Daily Average Flow – A constraint indicating the total volume of water that
must be released from a plant in a day, expressed as a flow.
Minimum Elevation – The lowest allowable reservoir elevation. At elevations below
the Minimum, the model will set the daily discharge to 0 cfs.
Minimum Flow Unit – A small unit that is installed specifically to generate power from
the minimum instantaneous flow when released through a low level outlet. Typically this

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unit is separate from the powerhouse, and therefore requires handling outside of the core
scheduling routines.
Minimum Instantaneous Flow – A constraint indicating the minimum flow of water
that must be released from a plant at all times of the day. This flow is available for
generation.
Natural Inflow – The inflow at a particular l would have received if there were no
upstream plants in the system. This flow is equal to the sum of all the upstream accretion
inflows.
Net Head – A measure of potential energy. The Net Head represents the effective head
under which the unit operates. The net head is the difference between the gross head and
the headloss.
Plant Operation Type - A reference to the manner in which water is scheduled through
a plant. At this time, there are six operating types:

Diversion Plant – A plant that can not control it’s daily release. A plant that uses
an uncontrolled outlet to divert water from one basin to another.
Fill and Spill – A plant that peaks with the loadshape but gives priority to the
upstream plant and will spill in order for the upstream plant to follow the
loadshape as closely as possible.
Non-Generating – A plant that peaks its discharge to follow the loadshape.
Strictly Peaking – A plant that peaks its discharge. Attempts to schedule water in
highest value periods of day. Can instantaneously (in a 15 minute
increment) change load.
Peaking with Ramp Rates – A plant where the water discharge still closely
follows the load shape (plant will peak); however, the plant is constrained
by ramping rates.
Pure Run of River – A plant where inflows are equal to outflows on an
instantaneous basis.
Re-Regulating – A plant designed to regulate peaked discharges from upstream
plants into smooth discharges. This plant releases constant outflows for

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the whole day. Re-regulating plants may or may not be constrained by
ramping rates. If so, then they are required to ramp between days.

Ramping Rates – Constraints on the rate at which a plant’s discharge can change.
Ramping Rate Curve – The river flow vs. stage curve relationship at the point where
ramping rate compliance is measured.
Reservoir – The water retained by a dam. Also referred to as headwater, storage,
forebay, or headpond.
Reservoir Storage Curve – A curve that defines a reservoir’s contents in acre-ft at
various surface elevations.
Scenario – A collection of settings that constitutes a CHEOPS™ model run. Output data
for a run are referenced by the scenario name.
Setting – A collection of conditions that form the building blocks of a scenario. A
setting is made up of conditions.
Sidestream Plant – A plant that is not on the main fork of the river. A plant that is
located on a side stream or minor tributary.
Spill – Water passed over a spillway without going through the units.
Spillway Capacity Curve – A curve that defines the maximum spill in cfs for the
spillway at given reservoir elevations.
Stage – The river surface elevation in feet based on a local datum.
Tailwater Elevation – The elevation where all energy from the water passing the turbine
has been extracted. (Can be the turbine centerline or the river surface elevation at the
point of powerhouse discharge)
Tailwater Curve – A curve that defines the tailwater elevation over the range of
powerhouse flows.
Turbine – A machine that recovers rotating mechanical energy from falling water.
Unit – A term referring to the combined turbine-generator machine.
Water Withdrawals-Water that is withdrawn from the reservoir, not available for energy
generation, that is lost from the system. Withdrawals can be either positive or negative.

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2.0 MODEL ARCHITECTURE________________________________
CHEOPS™ is a Microsoft® Windows® based software model that utilizes a back-end
Microsoft® Access 2000 database and a front-end Visual Basic 6.0® application. All
output data is contained in text files and can be viewed using pre-defined charts or graphs
in Microsoft® Excel.

For each CHEOPS™ model, DTA assembles the model from a library of standard
modules based on the unique physical and operational characteristics of the river system
or powerplant under consideration.
2.1 CONCEPT OVERVIEW
2.1.1 Scenarios
Because of the large amount of data involved in defining a hydro-system, the method of
data storage and retrieval in the CHEOPS™ model is somewhat involved. A CHEOPS™
model run is called a scenario. In other words, a scenario is made up of a particular set of
data that defines a combination of physical attributes and operational requirements that
make up one specific system configuration. For example, the “Existing System” scenario
would include all the data that defines the A scenario is a collection of settings. Each
scenario has a system setting and three additional settings (physical, operational and
generation) for each plant in the system. Each setting is a collection of conditions. The
conditions hold the actual input data that the model uses to simulate the system. A
schematic of the XXX PROJECT scenario object is shown below in Figure 2.1. The
remainder of Section 2.1 explains each of the settings and conditions.

INSERT FIGURE 2-1 SCENARIO BREAKDOWN (SHERRY’S POWERPOINT
PLOT)

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2.1.2 System Settings
The system setting consists of the conditions that refer to data applicable to either each
plant in the system or unique data solely applicable to one plant in the system. For
example the system setting includes the load shape condition which contains the data for
daily pricing and period hourly duration data. The load shape condition applies to the
entire system. The system setting also includes a toggle that controls the Gerle gate
automation. The Gerle automated condition applies to one plant and will not apply to any
other plant in the system. Each of the system setting conditions are discussed below.

2.1.2.1 Load Shape Condition
The load shape condition includes the data for the daily period durations and the daily
period pricing by each month. Each month the model allows the user to enter a weekday
load shape curve and a weekend load shape curve.

The weekday curve has seven periods made up of three different types of periods. These
three types are Peak, Secondary-Peak (or Shoulder-Peak), and Off-Peak. The user can
enter a value for off-peak generation, secondary-peak generation and peak generation in
dollars per MWh.

The weekend is limited to only a two types of periods; Peak and Off-Peak. The user can
then enter values for weekend off-peak generation and weekend peak generation in
dollars per MWh.

The model uses the load shape data to schedule the release of water throughout the day,
prioritizing generation during the higher value periods.

2.1.2.2 Capacity Prices Condition
The capacity price condition contains the monthly values for spinning reserve capacity.
The user can enter values for capacity in dollars per MW month by month. The energy
output viewer calculates dollar benefits for spinning reserve capacity using these prices in
conjunction with the load shape.

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2.1.2.3 Regulation Volume Condition
The regulation volume condition stores the volume that must be released, from XXX
Project, for system regulation purposes each month. The volume is entered in acre-ft
where a percentage of the volume has to be discharged during the peak period and if
necessary the shoulder-peak period of each day. The user can set a volume and
percentage by month.

The model uses this data to set minimum instantaneous flow releases from XXX Project
during the peak/shoulder-peak periods and during the off-peak periods. These minimum
releases simulate the District’s use of the XXX PROJECT system for system regulation.
This technique forces the model to release water during the off-peak periods.

2.1.2.4 Reserve Volume Condition
The reserve volume condition contains data that sets a minimum elevation at XXX
Project that must be maintained for peaking requirements. The model logic will use
water from the upstream reservoirs to maintain that elevation at XXX Project if it
becomes necessary.
2.1.2.5 Spinning Capacity Condition
The spinning capacity condition controls the amount of spinning reserve capacity set
aside for each plant in the system. The spinning reserve capacity for each plant is the
number of MW set aside for spinning reserve.

2.1.2.6 Carry-Over Elevations Condition
This condition controls how to treat the end and beginning of year elevations. The model
begins the run on January 1 of the start year with each reservoir at its target elevation. If
the run is a multi year run then the model can either start subsequent years with the
reservoirs at the target elevations or at the end of previous year elevations.

With Carry-Over Elevations is selected (the checkbox is checked), the model will carry-
over the end of year elevations to the next year and thus will start the next year a

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elevations that may be different from the target elevations. If Carry-Over Elevations is
not selected (checkbox is not checked) then the model will start each year with the
reservoirs at their target elevations.

Carrying over elevations can have a significant effect on the model results. If the user
runs “dry” hydrology and the reservoirs are drawn down the next year will have less
generation as the model refills the reservoirs. The reverse is true if the user is running
“wet” hydrology. It is important to understand the potential impact of this condition
when making multi-year runs with the CHEOPS™ model.

2.1.2.7 Forecast Set-Up Condition
CHEOPS™ can simulate the owner’s ability to forecast inflows to the system. The
forecast method requires two inputs, a number of forecast days and an accuracy of the
forecast. This condition has limited use for analysis; however, it can provide a very
rough estimate of the sensitivity of the system configuration to inflow forecast ability.

The number of days is how many days the model looks ahead in the inflow file to
calculate how much water the system is going to receive. Since the model has “perfect”
forecasting as it looks at the actual inflow file, the accuracy allows the user to adjust the
model’s ability to accurately forecast. The model looks ahead the given number of days,
adds up the inflows, and multiplies those inflows by the accuracy and schedules
discharges based on the forecasted inflow volume. If the accuracy is not 100%, then the
forecasted volume is not accurate. By running the model with 90% accuracy and then
running again at 110% accuracy the user can simulate operations where the owner has an
ability to forecast inflows plus or minus 10%.
2.1.3 Physical Settings
Each scenario contains a unique physical setting for each plant. The physical setting
contains the conditions that can be categorized as physical attributes of the system. The
conditions included in a physical setting are described below. It is important that all
elevation data be based on the same datum (mean sea level, for example) as the model
does some comparison from one plant to another.

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2.1.3.1 Reservoir Storage Curve Condition
The reservoir storage curve is the reservoir elevation vs. volume curve. The elevations
are in units of “ft;” the volumes are in “acre-ft.” The model uses this curve to calculate
elevations throughout the day based on inflows and model-determined discharges. Note:
the user must ensure that the reservoir storage curve exceeds the flood elevation (Section
2.1.4.1) so that the model has the ability calculate accurate reservoir elevations during
times of spill.

2.1.3.2 Reservoir Area Curve Condition
The reservoir area curve is similar to the storage curve except instead of elevation vs.
volume; it is elevation vs. surface area. The units for elevation are “ft” while the units for
surface area are “acres.” The model uses this data for daily evaporation loss calculations.

2.1.3.3 Daily Evaporation Condition
The daily evaporation condition contains daily evaporation coefficients for the plant by
month. The coefficient’s units are “ft/day.” To calculate evaporation the model
multiplies each day’s surface area by the month’s coefficient to get an evaporation
volume for the day in “acre-ft.” The evaporation volume is converted into a flow for the
day and is removed from the reservoir evenly throughout the day.

2.1.3.4 Tailwater Curve Condition
The tailwater curve is a curve that relates the tailwater elevation to the plant discharge.
The elevation is in units of “ft” while the plant discharge is in “cfs.” The model uses this
data to calculate a tailwater elevation from the instantaneous plant discharge. This
tailwater elevation is subtracted from the reservoir elevation to get the gross head driving
the unit. If the downstream plant’s reservoir elevation is higher than the calculated
tailwater elevation the model uses that downstream reservoir elevation as the tailwater
elevation in the gross head calculations.

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2.1.3.5 Spillway Curve Condition
The spillway curve contains the data relating reservoir elevation and spillway capacity.
The elevation is in units of “ft;” the spillway capacity is in units of “cfs.” This data
allows the model to determine the maximum amount of water that can be spilled at the
current reservoir elevation.

2.1.3.6 Ramp Rating Curve
The Ramp Rating Curve condition contains the data used to constrain a plant with
ramping rates. The curve is river stage vs. flow at the point of measured ramping rate
compliance. The elevation units are “ft;” the units of flow are “cfs.” The model uses this
curve to schedule discharges for plants that have ramping rates based on river stage. The
ramp rating curve elevation data is the one elevation that does not need to be based on the
common datum. The CHEOPS™ model is only looking at the curve to determine the
allowable rate of change for the current plant’s discharge.

2.1.3.7 Tunnel/Gate Curve
This condition contains the data describing the tunnel or gate discharge curve for
diversion or non-generating plants. This condition only applies to XXX. For the upper
two diversion reservoirs the curve is reservoir elevation vs. tunnel flow, while for XXX
the curve is reservoir elevation vs. gate discharge. In both cases the elevation is in “ft,”
and the flows are in “cfs.” The model uses these curves as the primary outlet for plants
without generating facilities.

2.1.3.8 Plant Options Condition
The plant options condition contains three pieces of information about the individual
plant. These three data values are: Penstock Capacity, Minimum Flow for Powerhouse
Operation, and Plant Operation Type.

The Penstock Capacity is a flow that is the maximum amount of water that can arrive at
the powerhouse. This is where the XXX PROJECT tunnel capacities should be entered
so the model will not schedule high discharges than the tunnel can handle.

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The Minimum Flow for Powerhouse Operation is the lowest flow that the powerhouse
will use for generation. This data allows the user to control the model discharges that
result in rough unit operation (only at the low end). Without this data and model will use
the full performance range of the units.

The Plant Operation Type is how the CHEOPS™ model classifies and operates the plant.
There are 6 plant operation types: Non-Generating, Strictly Peaking, Peaking with Ramp
Rates, Re-Regulating, Fill and Spill, Pure Run-of-River and Diversion Plant.

2.1.3.8.1 Non-Generating Plant
A non-generating plant is a plant that does not have a powerhouse but has the ability to
control discharges. .

2.1.3.8.2 Strictly Peaking Plant
A strictly peaking plant is a plant that can instantaneously peak from no discharge a
maximum discharge. It peaks powerhouse discharges to generate in the peak period, then
the secondary-peaks and then the off-peak periods. This type of plant can have a single
day double peak.

2.1.3.8.3 Peaking with Ramp Rates Plant
A peaking with ramp rates plant prioritizes its discharge in the peak periods but it is
constrained by ramping rates. This plant will not double peak but will ramp up to the
high daily discharge, remain at constant discharge and then ramp back down to the off-
peak discharge. This type of plant can handle ramping rates based on stage (feet/time) or
flow (flow/time). This Plant Operation Type must be selected if the user is
investigating ramping rates at a particular plant. It is not enough to simply enter in
some ramping rates. Both (Plant Operating Type set to Peaking with Ramp Rates,
and a Ramping Rate constraint imposed) must be entered for the ramping rates to
be used.

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2.1.3.8.4 Re-Regulating Plant
A re-regulating plant releases constant discharge for the entire day, ramps to the next
day’s discharge and releases constant flows again. This type of plant is usually found
downstream from a peaking plant (oftentimes the last plant in the system) because it can
smooth out peaked discharges. This Plant Operating Type also uses ramping rates to
determine how quickly the plant is allowed to change from one flow to another. If there
isn’t actually a ramping rate constraint at the re-regulating plant, then simply enter
extremely large ramping rate restrictions in the Ramping Rate constraint condition.

2.1.3.8.5 Fill and Spill
A fill and spill plant operates like a strictly peaking plant except that it is okay to spill.
This type of plant is usually found downstream from a much larger plant. The fill and
spill plant is usually undersized. Aggressive operation of the upstream plant is more
important than letting the model modify the upstream plant’s discharge to minimize spill
at the fill and spill plant.

2.1.3.8.6 Pure Run-of-River
A pure run-of-river plant releases its inflow on a 15-minute basis. This plant releases the
maximum of its capacity or inflow and spills the excess.

2.1.3.8.7 Diversion Plant
A diversion plant does not have a powerhouse and cannot control its discharge.
Discharge is based on the reservoir elevation. These plants do not use the load shape to
control their releases. XXX Project and XXX Project are diversion plants.

2.1.4 Operation Settings
Similar to the physical settings, operational settings are plant specific. Each scenario
contains one operation setting for each plant. The operation setting contains conditions
that control how the plant is operated: reservoir elevation constraints and required flow
releases. A complete breakdown of the operation setting is below. All elevations are in
units of “ft,” and they should be based on the same datum as the Physical Settings.

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2.1.4.1 Flood Elevation Condition
The flood elevation is the elevation at which the plant begins to spill. The elevation can
relate to a variety of physical situations (spillway crest, partial gate coverage, etc.), but it
represents the elevation at which the model will spill. When the model calculates an
elevation above this elevation the model will calculate spill as well. The model’s logic
attempts to reduce or eliminate occurrences when the reservoir elevation exceeds the
flood elevation. For plants with gates that control the spillway discharge, the flood
elevation should be the elevation at which operators start spilling to prevent overtopping.
For plants with uncontrolled spillway crests, the flood elevation is the spillway crest
elevation. The flood elevations can vary through the year. Note: the user must ensure
that the reservoir storage curve (Section 2.1.3.1) exceeds the flood elevation so that the
model has the ability calculate accurate reservoir elevations during times of spill.

2.1.4.2 Target Elevations Condition
The target elevations are the elevations at which the model tries to operate the reservoir.
These elevations can change each day and the model attempts to end each day at the
target elevation. This condition allows the user to control seasonal storage. By changing
the reservoir target elevations the model will either store or release water. The target
elevations should be less than the flood elevations and greater than the minimum
elevations.

2.1.4.3 Minimum Elevations Condition
The minimum elevation is the elevation is the minimum allowable reservoir elevation.
The elevation could be set by regulations or by a physical limit (lowest available outlet
invert). The model will operate to eliminate occurrences when the reservoir elevation
dips below this elevation. This elevation should be lower that the flood elevations and all
the target elevations.

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2.1.4.4 Water Withdrawal Condition
The water withdrawal condition allows the user to model water removal and return that
represents consumptive uses such as irrigation and municipal water sources. The model
allows the user to enter a daily withdrawal in cfs that is constant throughout the year and
a daily discharge in cfs that is constant throughout the year. The model then calculates a
net withdrawal and accounts for this withdrawal each day.

2.1.4.5 Fluctuation Limits Condition
Fluctuation limits are the maximum allowable change in reservoir surface elevation, from
maximum elevation to minimum elevation, within a single day. In other words it defines
the maximum difference allowed between the maximum elevation achieved on a
particular day and the minimum elevation achieved that day.

In addition to setting the maximum fluctuation for the day, the user can decide if the
limits are “hard” limits. Hard fluctuation limits reset the flood and minimum elevations
based on the fluctuation limits and the target elevation. If the user desires hard limits
then the user enters a percentage of the fluctuation limit that is above the target and the
model calculates the percentage that is below the target. An example is below:

If the target, flood and minimum elevations are xx ft, xx ft and xx ft
respectively; and hard fluctuation limits of xx ft are set with xx% below
the target; then for that day, the target elevation is still xx ft but the flood
elevation is now xx ft and the minimum elevation is xx ft.

This type of control allows the user to force the model to follow target elevations closer.
The difference between “Hard” Level Fluctuation Limits and regular limits (“Hard” is not
checked) is that the “Hard” limits will force the model to spill if the upper limit is
exceeded. Some other constraint or unusual hydrologic situation is forcing the reservoir
to go above the defined “Hard” limit which will result in the model spilling at that plant.

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2.1.4.6 Fluctuation Rates Condition
Fluctuation rates are similar to the fluctuation limits except fluctuation rates define the
maximum rate of change in surface elevation. For instance the model can have large or
no fluctuation limits but if the plant has fluctuation rates the model may be forced to peak
less aggressively if the reservoir surface elevation is changing too quickly. The
fluctuation rates are defined in “ft/hr.”

2.1.4.7 Minimum Instantaneous Flow Condition
Minimum instantaneous flows are flows that must be released either through low level
outlet or through the powerhouse 24 hours a day. The model will meet this requirement
before scheduling any excess water in the peak period.

The user can set the minimum instantaneous flow based on natural inflows to another
plant in the system. The minimum instantaneous flow can also be set based on inflow
bands at the other plant.

The user can set this constraint to an “or inflow” option. The “or inflow” option sets the
minimum instantaneous flow equal to the lesser of the user defined flow or the total
natural inflow into the plant. The total natural inflow is the sum of all the natural
accretions above the current plant. The natural inflow is NOT the sum of the upstream
plant’s discharge and the local accretion flows between the upstream plant and the
current plant.

2.1.4.8 Minimum Daily Flow Condition
The minimum daily flow condition represents the minimum volume, defined as a daily
average flow (cfs), that the plant must release for the day. The user can set the minimum
daily flow based on natural inflows to another plant in the system. The minimum daily
flow can also be set based on inflow bands at the other plant.

The user can set this constraint to an “or inflow” option. The “or inflow” option sets the
minimum daily flow equal to the lesser of the user defined flow or the total natural inflow

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into the plant. The total natural inflow is the sum of all the natural accretions above the
current plant. The natural inflow is NOT the sum of the upstream plant’s discharge and
the accretion flows between the upstream plant and the current plant.

2.1.4.9 Bypass Flow Condition
The bypass flow condition represents flows that are released into bypass reaches that go
around the powerhouse. Bypass flows are not available for generation. These flows have
units of “cfs” and the flow is released as a constant flow for the entire day. In addition to
setting the flow, the user sets a destination for where the flow will re-enter the system.
For example, Fish Ladder bypass flows have a destination of XX instead of the next
downstream reservoir, XXX Project.

The user can define this constraint as “or inflow.” The “or inflow” option sets the bypass
flow equal to the lesser of the user-defined flow or the total natural inflow into the plant.
The total natural inflow is the sum of all the natural accretions above the current plant.
The natural inflow is NOT the sum of the upstream plant’s discharge and the accretion
flows between the upstream plant and the current plant.

2.1.4.10 Ramping Rates Condition
The ramping rate condition controls how the model changes a plants discharge. This
constraint is only used if the Plant Operations Type is set to peaking with ramp rates or
re-regulating. The user can set separate rates for increasing discharges and decreasing
discharges. The user can also set separate ramping rates for hourly and daily ramping.
The ramping rates can be defined as the allowable change in river stage per time (ft/hr
and ft/day) or flow per time (cfs/hr and cfs/day). When ramping rates are defined as
stage/time, the relationship is defined by the ramp rating curve in the physical setting.
Flow based ramping rates do not require that the user enter a ramp rating curve.

2.1.4.11 Flashboards Condition
The flashboard condition allows the user to install and remove flashboards. Currently the
methods that install and remove flashboards are: Day, Flow and Elevation. Flashboards

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can be located on the spillway, as is the case with most projects or in the tunnel as is the
case with XX and XX. Along with controlling the installation and removal of the
flashboards, the flashboard condition contains the discharge curve (flow vs. elevation) for
the outlet when the flashboards are installed.

With the Day control the user can specify that the flashboards be installed or removed on
a certain day of the year. This option gives the user the ability to simulate flashboards
that are used to regulate seasonal reservoir elevations.

With the Flow control the user can simulate flashboard installation and removal based on
inflows to the project. When the inflows drop to a user defined average over a user-
defined number of days, the flashboards are installed or removed.

With the elevation control the user can simulate flashboards the break out as the reservoir
elevation increases. The flashboards are removed at the user-defined tripping elevation,
while the model assumes that new flashboards have been installed when the reset
elevation is reached (provided the flashboards are currently removed/tripped).

2.1.5 Generation Settings
Generation settings are plant specific and contain the data necessary to simulate power
generation. The data includes turbine performance, generator performance, headloss
data, gate leakage, unit outages and low-level outlet generating units. This data,
combined with the physical and operational data, allows the model to estimate generation
on a 15-minute schedule.

2.1.5.1 Turbine Generator Condition
The turbine generator condition contains data describing each turbine generator in the
plant. Everything from the performance of the turbine and generator to the headloss and
gate leakage is included in this condition.

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2.1.5.1.1 Headloss Component
The CHEOPS™ model allows two common headloss coefficients for the plant and an
individual coefficient for each unit. The user associates each unit with a common
coefficient. Headloss for each unit is calculated by multiplying the unit’s common
coefficient by the total flow for that common coefficient squared added to the individual
coefficient multiplied by the individual unit flow squared. The formula is included
below.
iic
n
j
ji hFhFH2
2
1
+




=∑
=

Where:
Hi is the unit headloss in feet
hc is the common coefficient for the ith unit
hi is the individual coefficient for the ith unit
Fi is the flow for the ith unit
j runs from 1 to n
n is the number of units that have the same common coefficient as the unit i

2.1.5.1.2 Turbine Component
Turbine performance is entered by plant. During plant set up the performance data is
assigned to a particular unit. Each turbine performance data set can be assigned to
multiple units, so if the plant has three identical units, the performance data set is only
entered once.

The performance data is entered as flow vs. efficiency at five separate net heads. These
net heads must span the entire performance range with which the units will be subjected.
The performance data must have a minimum of three data points, indicating minimum
operating flow, peak operating flow and maximum operating flow. The user does not
need to truncate the turbine performance data (please enter the range of turbine
capabilities) due to generator or auxiliary equipment limitations.

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If the turbine performance data is available as combined turbine/generator data, enter the
turbine data and create a generator performance data condition with generator efficiencies
of 100% (see Section 2.1.5.1.3).

2.1.5.1.3 Generator Component
The generator data, like the turbine data, is entered by plant and then associated with a
unit. Again, if the plant has three identical generators, the performance data need only be
entered once. The generator performance data is generator output vs. generator
efficiency.

The generator condition includes a maximum generator output. This value is the
maximum generator output the model will allow assuming that there is turbine capacity
to meet this limit. This feature allows the user to limit generator outputs if other auxiliary
equipment can not handle maximum generator output. The model will limit turbine
output based on the generator maximum desired output.

2.1.5.1.4 Gate Leakage Component
Gate leakage is the amount of water that leaks through the wicket gates when the turbine
is off-line. The model leaks this amount of water when that unit is off-line. For instance
if the powerhouse has three units each with gate leakage of 15 cfs, if units 1 and 2 are
operating and unit 3 is off-line, then only unit 3 is leaking 15 cfs. When a unit is out for
maintenance it’s gate leakage is assumed to be zero.

2.1.5.2 Maintenance Schedule Condition
The maintenance schedule provides the model with those units that are out of service for
the scenario run. With this condition the user can analyze the impacts of major unit
rehabilitation. This feature is not designed to simulate one or two day unit outages. This
feature is for long, multi-week outages. The maintenance schedule allows the user to
remove one unit from service at a time.

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2.1.5.3 Minimum Flow Unit Condition
The minimum flow unit models low level outlet generating units. This condition contains
the necessary data to calculate the energy generated by a minimum flow unit. This
condition requires headloss, generator performance, turbine performance and rated net
head data for the minimum flow unit.

There are two main types of Minimum Flow units. The first type operates 24 hours a day
and uses the bypass flows as its flow source. The second type operates during those
periods when the main powerhouse is not running.

2.2 UNIT DISPATCH
The model uses the unit dispatch to predict generation based on the user provided
turbine-generator data. The purpose of the unit dispatch is to produce a plant generation
matrix or lookup table where plant generation (MW) is plotted against gross head and
total plant flow. The model will use this lookup table to calculate plant generation in MW
every 15 minutes. The Output Lookup Table is only created once for each Turbine-
Generator Condition.

The first step of the process is to generate a unit dispatch table so the model knows the
best way to distribute flows between the units. This step is also referred to as producing
the optimal unit dispatch solution. The unit dispatch logic begins with very small plant
flows. The routines calculate the optimal unit dispatch for each small flow. The rough
estimate of the individual unit distribution is fine-tuned using partial differential
equations to arrive at an optimal distribution for the given flow. The fine tuning process
incrementally adds and subtracts flow from the units to hone in on the maximum possible
generation for the given total plant discharge. As the plant dispatch routine increases the
total plant flow the model uses the previous unit dispatch distributions as well as new
distributions to find the largest possible generation given the plant discharge. In this way
the model is using previous solutions to “learn” about future solutions. The final result is
a collection of flow distributions by unit for the entire range of plant operating flows.

Page 23

To calculate the plant generation the unit dispatch table, as calculated in the previous
paragraph, is used, in combination with a span of gross operating heads, to calculate the
plant generation. The model has everything required, total plant flow, flow distribution
between the units, headloss for each unit and the plant gross head. The final result is the
plant generation matrix of plant output (MW) based on plant gross head and plant total
flow.

2.3 DAILY TIME STEP LOGIC SEQUENCE
The ultimate CHEOPS™ output is a 15-minute, detailed schedule of plant releases and
generation. An intermediate step in producing the 15-minute schedule is calculating the
daily inflows, discharges and elevation targets for each plant in the system. This section
will detail the method used to get the daily average plant discharges.

2.3.1 Retrieval of Constraint Data
The first step in the plant loop is to retrieve the constraints for that plant for that day. The
model calculates the target elevation, minimum flows, bypass flow, water withdrawals,
etc. Anything for that plant for that day that is day specific is calculated and loaded into
the model logic.

2.3.2 Sum of Inflows
With all the daily constraint data loaded into the model, the model then retrieves the
upstream plant’s discharges for the day, local accretions and any other bypass flows and
or spill flows that will arrive at that plant. The model sums these inflows and calculates a
detailed 15-minute inflow profile for the plant.

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2.3.3 Daily Discharge Calculation
After the model determines the inflow volume for the plant it calculates a daily average
discharge. The daily average discharge is a function of the total daily inflow, forecasted
project inflows, target elevations, plant capacity and minimum release requirements.

With the daily discharge calculated the model checks the discharge against daily
constraints such as minimum daily average flows, minimum instantaneous flows,
downstream requirements and minimum and flood elevations. Adjustments are made to
the daily average discharge as necessary to meet the plant constraints.

2.4 15-MINUTE TIME STEP
Once the daily average flows have been set, the model schedules the plant’s 15-minute
discharge. The first priority is to meet the minimum instantaneous flow for the plant.
This minimum instantaneous flow volume is removed from the volume available for
peaking purposes. All daily constraint flows were accounted for in the derivation of the
daily discharge volume. The primary guide for the 15-minute schedule is the loadshape.

2.4.1 Discharge priorities based on loadshape
The loadshape contains the period durations for each month for both weekdays and
weekends. The model uses this data to create the 15-minute schedule along with the
plant’s peak unit capacities. The model allocates the peaking volume of water into the
peak periods first, the period between peaks, the secondary peak periods and finally the
off-peak periods. The model attempts to operate the units at peak efficiency in order to
maximize the generation for the period.

If the plant has ramp rates the model will schedule the plant to not violate the ramp rate
requirements. If the plant is re-regulating the model will schedule a flat discharge
characteristic of a re-regulating facility. If the plant is a run-of-river plant the model will
schedule discharges to match the inflows.

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2.4.2 Constraint Checking
After the peaking volume has been schedule the model calculates 15-minute reservoir
elevations based on the 15-minute inflows and discharges. With the elevations the model
will check for reservoir constraint violations. If violations are found the model will
incrementally shift water either at the current plant or the upstream plant to remove
reservoir violations. When the violations are eliminated the model proceeds to the next
downstream plant.

2.5 MODEL LOGIC FLOW CHART
The following two figures give an overview of the model logic in sequence.

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Text files are created and stored
in model directories
Output Generated (text files):
Daily summaries and/or Detailed
schedules
Create Conditions needed for
new Scenario
Create Settings needed for new
Scenario
Create new Scenario
Run new Scenario(s)
Select the type of Run to make:
Energy or Rule Curve
Model Executes using data of
selected Scenario (see following
page)
Steps to create a
new Scenario
Create Components if needed for
new Conditions
View Output and create summary
charts and tables
Select hydrologic period to
include in model run
CHEOPS™ Model Execution Flow Chart

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Determine "Optimal" Detailed
Discharge Schedule.
Determine Daily Discharge Volume
(Average Daily Discharge)
Determine Inflows (Detailed and
Total Volume)
Check for Elevation
Constraint Violations Yes
Make adjustments to the detailed
discharge schedule of current
and/or upstream plant
Calculate Spill (if any)
No
Calculate Energy
Calculate Detailed reservoir
elevatoins
CHEOPS™ Scheduling Flow Chart

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3.0 USER’S MANUAL________________________________________
This section contains screen shots and descriptive text to enter and modify system data,
run the model and view the CHEOPS™-generated output. Also included are brief
descriptions on where and how the model uses each piece of data. Refer to Section 2 for
detailed analysis about how the model logic works.
3.1 MAIN MODEL INTERFACE
The main CHEOPS™ interface as shown below in Figure 3-1 is the base point for the
model navigation. From this point the user can view individual plant data, system data,
create a model scenario, run the model and examine CHEOPS™ output.

Figure 3-1 Main CHEOPS™ Model Interface

3.1.1 Saving Data interface
The CHEOPS™ model built from input data. All the data must be saved to the database
for the model to incorporate the data. Retrieving and saving this data is done using
almost identical interface screens. These screens are described and shown below.

3.1.1.1 Retrieving Data
The interface screen for retrieving data is shown below in Figure 3-2. To retrieve data
the user selects the data from the dropdown box and clicks on the “Open” button. As the
dropdown box changes the notes and description text boxes update with text that was
entered when the data was last saved. The user can delete data from the dropdown box
by selecting the data and clicking on the “Delete Data” button. The model does not allow
the user to delete Base Case data. The user can save over the Base Case data but can not
delete it completely.

Figure 3-2 Retrieving Data

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3.1.1.2 Saving Data
The save data interface is almost identical to the Retrieving interface discussed in the
previous section. The Save Data interface is shown in Figure 3-3. The noticeable
differences between Save and Retrieve are the “Open” button is now a “Save As” button
and the “Delete” button is always disabled. The user cannot delete data while saving
data. Now the dropdown box, in addition to all the previously saved data sets, includes a
set called “New Data”.

Figure 3-3 Saving Data

To save a new set of data the user should select the “New Data” case from the dropdown
box. Fill in the notes and description if desired and click the “Save As” button. The
model will ask for a name for the data set, enter a new name, click “OK” and the model
will save the data.

To replace another data set select the name of the data set, modify the notes and
description as necessary and click the “Save As” button. The model will warn the user of
the impacts of saving over the data. If the user decides that this is desired then click
“OK”, otherwise, click “Cancel” to leave the selected data setting.

3.1.2 Individual Plant Condition Interface
The plant interface is the base navigation point for entering plant specific data. To get
the plant interface click on either the “Select Plant” button from the main interface in
Figure 3-1, or click on the plant name in the picture in Figure 3-1. The plant interface is
shown below in Figure 3-4. XXX Project , XXX Project and XXX Project have some
of the plant data options disabled, as these data options do not apply to these plants.

Figure 3-4 Plant Interface

On the left side of the interface are frames containing conditions for the three different
settings. Please refer to Section 2.1 for an overview of scenarios, settings and conditions.

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Scenarios are made up of settings and settings are made up of conditions. On the right
side of the form below the picture are the setting buttons where the user can create a
setting.

3.1.2.1 Physical Conditions
Physical settings represent the data that simulates the concrete and rock structues. The
techniques to input this type of data are included below.

3.1.2.1.1 Reservoir Storage Curve, Reservoir Area Curve, Daily Evaporation,
Tailwater Curve, Spillway Curve, Ramp Rating Curve

These data sets are all entered using the same technique. The basic data entry interface is
included below in Figure 3-5. Specifically, Figure 3-5 represents the reservoir storage
curve for Loon Lake.

Figure 3-5 Basic Data Entry for Physical Conditions

To enter data each line of data is entered in the boxes and the “Add Data” button is
clicked. The model will insert the data into the correct position. To delete a line of data,
click on the data line in the data grid and then click the “Delete Data” button. The user
can open data by clicking on the “Open” button. Once the user has changed the data the
model will enable the “Save” button and the user can save the data.

The interface for the other physical conditions is almost identical with the exception of
units and some wording. The difference for daily evaporation is that the coefficients
entered are constant for the month entered and if the user does not enter data for a month
the model will fill in a zero for that months coefficient.

3.1.2.1.2 Plant Options
The plant options interface is different than the other physical condition interfaces. This
interface allows the user to enter the four pieces of plant data that form the plant options
condition. These pieces of data are the penstock capacity, minimum daily flow for

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powerhouse operation, minimum daily rule curve flow and plant operation type. A
description of this data is included in Section 2.1.3.8. The interface is shown below in
Figure 3-6. If there is no penstock capacity limit uncheck the “Define Penstock
Capacity” check box.

Figure 3-6 Plant Options Interface Form

3.1.2.2 Operational Conditions
The operational conditions represent data that can vary by day throughout the year and
data that is usually driven by regulatory constraints. Descriptions of how the model uses
this data can be found in Section 2.1.4.

3.1.2.2.1 Flood Elevations, Target Elevations, Minimum Elevations

The flood elevations, target elevations and minimum elevations are all entered the same
way. The user selects a day of the year, enters the corresponding elevation and clicks the
button to add data. The user can enter as many dates as necessary and as few as 1 day.
The model will calculate an elevation for January 1 and December 31 from the data
provided by the user. The user can delete an elevation by selecting the elevation and then
clicking on the “Delete Data” button. The elevations interface is shown below in Figure
3-7.

Figure 3-7 Entering Flood, Target and Minimum Elevations

The model will calculate the elevations for in between days by linear interpolation.
Using Figure 3-7 as an example, on February 1 the model will calculate a target elevation
for Loon Lake right of approximately 6377.25 (the value half way between the elevations
for January 1 and March 1).

3.1.2.2.2 Water Withdrawals
The water withdrawal interface is fairly simple as the model only handles a constant
water withdrawal for the year. The interface, as shown in Figure 3-8, requires that the

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user enter two numbers. One number is the flow of water removed from the reservoir
each day for consumptive purposes and the flow of water returned to the reservoir each
day.

Figure 3-8 Water Withdrawals

3.1.2.2.3 Fluctuation Limits and Fluctuation Rates

The fluctuation limits and rates controls how much the model can manipulate the
reservoir surface elevation within the day. The interface for these conditions is similar to
the interface for the elevations as show in Figure 3-6. However the interface for the
fluctuation limits, as shown in figure 3-9, has an added check box, that when checked
opens additional data entry fields.

Figure 3-9 Fluctuation Limits

Hard Limits control how stringently to hold the reservoir to the target elevation. If “hard
limits” are selected then the model will not operate the reservoir above the hard limit or
below the hard limit. For example: if the model’s target elevation is 1200 ft, the
fluctuation limit is a hard 4 ft limit with 75% of the limit above the target, then the model
will keep the reservoir between 1203 ft (75% of 4 ft above the target -- .75 * 4 ft + 1200
ft = 1203ft) and 1199 ft (25% of 4 ft below the target – 1200 ft – (.25 * 4 ft) = 1199 ft).
This feature allows the user to control the daily fluctuations in an envelope around the
target elevation. Hard limits are explained in greater detail in section 2.1.4.5.

The fluctuation limit and rates do not get interpolated like the elevations for in between
days. If the user enters a fluctuation limit of 3 ft on January 1 and 2 ft on January 15,
then the fluctuation limit on January 14 is 3 ft.

3.1.2.2.4 Min Instantaneous Flow and Min Daily Average Flow

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Each of the two minimum flow conditions can be defined in two different ways. The
minimum flows can be a predetermined set flow or they can be set based on inflows to
another plant in the system.

If the min flows are set independent of inflows to other plants, then the interface is
similar to the elevation interface. The user selects a day and a minimum flow and adds
that data to the data grid. This basic interface is shown below in Figure 3-10

Figure 3-10 Minimum Flow Conditions

The minimum flow conditions have an “Or Inflow” option. The “Or Inflow” option
allows the model to limit the required minimum flow based on the plant’s inflows. If a
plant has a minimum daily average flow of 35 cfs but the plant’s natural inflow for the
day was 32 cfs, the model would reduce that day’s minimum daily average flow
requirement to 32 cfs. The model will not allow negative minimum flows. The natural
inflow for a plant is considered the sum of all the upstream inflows for each day.

The second way the minimum flow requirements can be defined is based on the inflows
to another plant in the system. In other words the minimum flow required is dependent
on the amount of inflow at some location in the river system. If the minimum flows are
based on inflows to another plant the minimum flows are defined with a day and a
dependency relationship as shown below in Figure 3-11.

Figure 3-11 Minimum Flows based on Dependencies

All the dependencies are in the dropdown box and the user can set up dependencies by
clicking the “Dependencies” button. The “Or Inflow” option is overriding and if it is
checked, after the day’s minimum flow has been calculated based on the other plant’s
inflows it is checked and changed if necessary.

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The form to set up dependencies is below in figure 3-12. Dependencies are set up based
on inflow ranges for the dependency plant. If the dependency plant inflow is below the
lowest range the minimum flow for the lowest range is used. If the dependency plant
inflow is higher than the highest range then the minimum flow for the highest range is
used. If the “Or Inflow” option is selected, if the defined minimum flow is lower than the
dependency plant’s inflow, the minimum flow for the plant is set to the inflow of the
dependency plant.

Figure 3-12 Dependencies Interface

The days dropdown sets the number of days used to average inflows to the dependency
plant. The dependency plant’s inflow is a rolling average inflow instead of a single day
inflow. To use a single day inflow set the number of days to one.

Minimum flows are not interpolated but held constant like the fluctuation conditions. If
the minimum instantaneous flow for a plant was 50 cfs on January 1 and 25 cfs on
January 15, then on January 14 the model uses a minimum instantaneous flow
requirement of 50 cfs.

3.1.2.2.5 Bypass Flow

The bypass flow interface is similar to the elevations interface, however like the
fluctuation conditions and the minimum flow conditions the flow values are not
interpolated for days between the control days. The interface is shown below in Figure 3-
13.

Figure 3-13 Bypass Flows

The bypass flows like the minimum flows have an “Or Inflow” option. Bypass flows do
not go through the powerhouse and they can return to the system at any downstream
plant. An example is for XXX Project as shown above, the bypass flows return to

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Junction as while the powerhouse flows go to XXX Project. The user can specify that
bypass flows never return to the system.

3.1.2.2.6 Ramping Rates

Ramping rates are similar to the fluctuation, minimum flow and bypass flow conditions.
Ramping rates change each day and are not interpolated. The interface for the ramping
rates is below in Figure 3-14. The model allows the user to enter separate rates for hourly
and daily ramping rates as well as allowing them to be both defined separately for the up-
ramp and the down-ramp. In addition the ramping rates can be defined as stage per time
or flow per time. Note: If the rates are stage per time the user must include a ramp rating
curve in the physical settings.

Figure 3-14 Ramping Rates

3.1.2.2.7 Flashboards

Flashboards are calculated as described in Section 2.1.4.11. The user can control the way
the flashboards are removed and installed through the year. Besides controlling removal
and installation, the interface shown in Figure 3-15 requires the user to enter a discharge
curve. When the flashboards are in place the model will use the flashboard condition
curve instead of the spillway curve. Logically, when the flashboards are removed the
model will resume using the spillway curve.

Figure 3-15 Flashboards

3.1.2.3 Generation Conditions

The generation conditions are conditions directly related to power generation. These
conditions and components are described more in detail in Section 2.1.5.

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3.1.2.3.1 Plant Set-Up

The plant set up dialog is where the user can create the plant with which the model will
generate power. The plant set-up interface is shown in Figure 3-16. The user selects a
headloss component, which sets the headloss for the plant as well as the number of units
in the plant. The user can then select turbine and generator performance and gate
leakage for each unit. The headloss, turbine and generator component set-ups are
included in subsequent sections.

Figure 3-16 Plant Set-Up

Once the user has set up the plant the user can either immediately dispatch or dispatch
during run-time. When the model runs a scenario it will automatically dispatch any
plants that have not previously been dispatched.

3.1.2.3.1.1 Headloss

The headloss interface is where the user can control the number of units in a plant. As
shown in Figure 3-17, the “Change Number of Units” button controls this feature.

Figure 3-17 Headloss Interface

With the number of plants selected the user enters the individual headloss coefficients
and decided which common coefficient to assign to each unit. The concept of multiple
common coefficients is explained in more detail in Section 2.1.5.1.1.

3.1.2.3.1.2 Turbines

The turbine component contains the turbine performance data. CHEOPS™ turbine data
is presented as flow vs. efficiency at five net heads as shown in Figure 3-18.

Figure 3-18 Turbine Performance

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The first step in setting up the turbine performance data is to click the “Set Up Heads”
button and enter the five net heads for the performance data. Once the heads have been
entered the user can enter each flow and efficiency by hand, estimate performance based
on a single curve or import the data from a provided Excel template.

To enter flows and efficiencies by hand click on a cell and type in the data. All
efficiencies must be between 0 and 1 representing 0% to 100%. The user can also left
click on a cell or range of selected cells to get delete and insert functionality.

To enter the data based on a single curve click on the “Create from One Curve” button
and the interface in Figure 3-19 will open. The user can then enter a single curve at one
head, which must lie inside the defined head range, select the creation mode and click on
the “OK” button.

Figure 3-19 Create from One Curve Turbine Performance

If the “Laws of Similitude” option is checked the model will estimate the performance
data based on laws of similitude. The “Constant Performance” option estimates the rest
of the turbine data with data that is identical to the entered curve.

To import turbine performance from the Excel template, the user needs to open the file
called “Tubine.xls” in the ExcelFiles folder in the CHEOPS model directory (default of
c:\Program Files\Cheops). Enter the performance data into the template. Save the
template as a new file. Then click on the “Import from Excel” button. The model will
open a standard windows open dialog, select the saved turbine data file and click on the
“Open” button. The model will then copy in the performance data from the Excel file.

3.1.2.3.1.3 Generators

The generator data is similar to the turbine data except that there is no range of heads to
enter. The interface as shown in Figure 3-20 also includes a “Maximum Generator

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Capacity” value that can be entered by the user. This capacity is designed to represent
the largest power output that the model will allow the generator terminals to produce.
This feature allows the user to impose constraints on the system if other auxiliary
equipment have capacities that control plant generation.

Figure 3-20 Generator Interface

The generator data can be imported from Excel if the user has created an Excel data file
from the provided generator template. This import function works similarly to the
turbine data importing discussed previously in this section.

3.1.2.3.2 Maintenance Schedule

The maintenance schedule is like every other day based data condition. For the
maintenance schedule the user enters a day and the unit that is out for that day. If a unit
is scheduled out, the model will not bring that unit back on line until the model is told
that zero units are out. For example: If the user enters that Unit 1 is out on January 15
and Unit 5 is out on January 18 the model will operate with Unit 1 unavailable for
generation on January 15, 16 and 17 and then unit 5 will be unavailable for generation
from January 18 until the end of the year. If the user entered that unit 0 was out on
January 17 and unit 0 was out on January 19 then unit 1 would be unavailable for
generation on January 15 and 16 and unit 5 would be unavailable for generation on
January 18. On January 17 all units would be on line.

3.1.2.3.3 Minimum Flow Unit

The minimum flow unit interface allows the user to enter data characterizing a small unit
that generates with flows released from a low-level outlet.

As was discussed in detail in section 2.1.5.3 there are two types of minimum flow units.
The first type of minimum flow unit only operates when the scheduled powerhouse flow
is less then the smallest flow that can spin the smallest turbine in the main powerhouse

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based on the turbine performance data. The minimum flow unit will operate when the
model is not releasing enough water to generate at the main powerhouse. The model only
releases small volumes when it has to for a minimum instantaneous flow. With this first
type of minimum flow unit, the plant cannot generate with bypass flows.

The second type of minimum flow unit operates 24 hours a day using the required bypass
flow as the power source.

The interface for the minimum flow unit is below in Figure 3-10. The user can enter
turbine performance at one head (model assumes constant performance over all heads), a
rated net head, a headloss coefficient, a turbine centerline elevation that the model will
use to calculate gross head and a flat generator efficiency.

Figure 3-21 Minimum Flow Unit Interface

3.1.2.4 Plant Settings
The previous sections have described entering and editing condition and component data.
The CHEOPS™ is set up so that components form conditions, conditions combine into
settings and finally settings combine into scenarios. This section will discuss the creation
of settings.

For each setting interface with a double click on the label for a condition the model will
open that condition’s interface and allow the user to modify data in that condition. If the
user right clicks on the label the notes and description of the selected data set will open
for reference.

3.1.2.4.1 Physical Setting

The physical settings interface button can be found on the right hand side below the plant
image in Figure 3-4. The user can click this button and the interface shown below in

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Figure 3-22 will open. Creating the setting is simple; select a condition for each
dropdown box and save the setting. If the dropdown box contains an option of “None”
then the condition is optional. The user can not select a evaporation condition unless a
surface area condition has been selected. This interface control was included because the
model must calculate the reservoir surface area before it can calculate evaporation. Save
this setting and the name will become available when the user wants to create a scenario.

Figure 3-22 Physical Setting Interface

3.1.2.4.2 Operational Settings

Creating an operational setting is the same as creating a physical setting. Simply select a
condition for each dropdown box and save the setting. The setting will then be filled into
the correct dropdown when the user creates a scenario. The operational setting interface
is shown in Figure 3-23.

Figure 3-23 Operational Setting Interface

3.1.2.4.3 Generation Settings

A generation setting is created the same way the other settings are created. The user can
not have a maintenance schedule if the plant does not have a powerhouse. See the
generation setting interface in Figure 3-24.

Figure 3-24 Generation Setting Interface

3.1.3 System Setting Interface

The system setting interface contains dropdown boxes and checkboxes so the user can
create a system setting as well buttons that allows the user to get to the interfaces to
create the conditions that make up the system setting. The system setting is shown below
in Figure 3-25.

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Figure 3-25 System Setting Interface

The “Carry Over Elevations” checkbox controls how reservoir elevations should be
carried over to the next year in a multi-year run. This option does nothing if only a single
year is being simulated. If checked the model will carry over the elevations, if unchecked
the model will start each year with the reservoirs at the target elevations.

The “Automate Gerle Gates” checkbox controls the Gerle Gate Automation. If checked
the model operates with the assumption that the gates are automated to open and close on
a daily basis, if unchecked the gates remain open at all times.

The forecast set-up controls how the model estimates future inflows to the projects. The
number of days represents how many days the model looks ahead to anticipate inflows.
The accuracy box contains a number that represents the accuracy of the model’s ability to
look forward. Since the model has perfect vision with the inflow file, after the model
adds up all the future inflows it multiplies the sum by the number in the accuracy box. If
the user would like to see how well the model operates assuming a plus or minus 20%
accuracy, run the model once with the accuracy at 1.2 and then again with the accuracy at
0.8.
3.1.3.1 Load Shape

The loadshape condition provides the data necessary for the model to prioritize different
periods during the day. The load shape interface is shown below in Figure 3-26. The
user selects the duration in hours for each of the periods, both weekday and weekend.
The plot updates automatically with the durations and allows the user to graphically see
the daily load shape. The plot does not represent the price differences graphically. The
user can scroll through the months using the month control buttons at the top and the user
can copy the previous month’s loadshape into the current month.

Figure 3-26 Load Shape Interface

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3.1.3.2 Capacity Prices

Capacity prices are the values in dollars per MW-month for spinning reserve. This data
is used by the model, in the energy output viewer, to assign dollar benefits to the spinning
reserve. The interface for the capacity prices is shown below in Figure 3-27. This
interface is similar to the evaporation condition interface and for months the user leaves
out, the model will use a capacity price of 0 $/MW-month.

Figure 3-27 Capacity Prices

3.1.3.3 Regulation Volume
The regulation volume for the model is the volume of water that must be released from
XXX Project to simulate DISTRICT’s use of the XXX PROJECT for regulation
purposes. In addition to the volume that XXX Project must release each month, is the
percentage of that volume that must be released during the peak period. The regulation
volume interface is shown in Figure 3-28.

Figure 3-28 Regulation Volume

3.1.3.4 Reserve Volume
The reserve volume represents the minimum amount of volume that must be kept in the
XXX PROJECT storage reservoirs each month to ensure that the model will not cause
operations that deviate from the District’s system rule curve. The reserve volumes also
ensure that the model carries over enough water for operations in back to back dry years.
The reserve volume interface is shown below in figure 3-29.

Figure 3-29 Reserve Volume

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3.1.3.5 Spinning Reserve
The spinning reserve interface, as shown in Figure 3-30, is where the user can indicate
how many megawatts of system capacity are set aside for spinning reserve. The model
will attempt to limit plant operations to maintain this amount of reserve at all times
except during spill. When a plant spills the model does NOT make up the spinning
reserve amount at another plant.

Figure 3-30 Spinning Reserve

3.1.4 Set Up and Run Scenario Interfaces

When the user has entered all the data and created all the settings, creating a scenario is
similar to creating a setting. The scenario set-up interface, as shown in Figure 3-31,
contains dropdown boxes that contain the settings for each plant in the appropriate place.
The user selects the system setting and a physical, operational and generation setting for
each plant and saves the scenario.

Figure 3-31 Scenario Set-Up Interface

To run a scenario the user opens another interface as shown in Figure 3-32. This
interface allows the user to select multiple scenarios and run those scenarios back to back
for set years. The user selects a scenario in the dropdown list and adds that scenario to
the list. The user can also delete scenarios from the list. The user can either run the rule
curve portion of the model or the energy portion of the model.

Figure 3-32 Run Scenario Interface

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The Rule Curve Model runs through the scenarios and calculates the daily discharges,
inflows and elevations for the period. The Energy Model calculates the daily variables
(just like the Rule Curve model), the 15-minute schedule and the simulated generation.

If the user wants to run the Energy Model, the model will ask the user if they want to
save the detailed data. A basic Energy Model run saves the daily variables and the daily
energy production by period. The detailed data contains the 15-minute operations for
each plant in the period run. If the user saves the detailed data, the model will produce
detailed data output files for each plant for each year. Each detailed daily output file is
approximately 3 Mb in size. The user should only save the detailed data to view and
analyze the 15-minute system operation. Daily analyses can be done without saving the
detailed data. Hard drive space can be used up very quickly if the user makes a number
of runs while saving the detailed data.

The model will then ask the user what years to run using the interface shown in Figure 3-
33. The user selects a start year and an end year. The model will run each of the
scenarios from January 1 of the start year through December 31 of the end year.

Figure 3-33 Period of Record Interface

The model will display a status bar of the model operation. The title of the status bar will
inform the user which scenario is being run and the status bar label will provide the user
with information as to what the model is calculating. Not all the days will take the same
amount of time. Some days require more calculations than others and may take as long
as a couple of minutes.

When the model is done calculating it will return to the interface in Figure 3-32. The
user can then return to the main interface and view the output.

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3.1.5 View Output Interface

From the main interface in Figure 3-1, the user can click on the “View CHEOPS Output”
button to open the Excel based output viewers. The next interface that opens is shown
below in Figure 3-34. From this interface the user can choose to view the rule curve
output by clicking the “View RC Data” button, to view the 15-minute schedule the user
clicks the “View Details” button and to view the energy production the user clicks the
“View Energy Data” button. These buttons will open up the Excel based viewers for
each option. See sections 3.2 to 3.4 to operate the Excel based output viewers.

Figure 3-34 Output Options

3.2 RULE CURVE OUTPUT VIEWER INTERFACE
The rule curve output viewer is an Excel file named “RC Output.xls”. This file is located
in the Output folder in the CHEOPS™ model directory. The “RC Output.xls” file
contains internal macros and worksheets designed to sum and tabulate the Rule Curve
output data. The data can then be plotted and viewed in various formats. The main
interface, as shown below in Figure 3-35, will open automatically when the “View RC
Data” button is clicked in the view output interface.

Figure 3-35 Rule Curve Output Viewer

The first step is to load the scenario data. Click on the “Load Scenario Data” button and
select the scenario to load. Note: the user must re-open the output viewer from the main
CHEOPS™ program to get the most up to date scenarios. If the viewer is open and the
user runs another scenario, the viewer will not include the new scenario results until the
viewer has been re-opened from the main CHEOPS™ program. To look at the data
behind the plots, the user must export the plot and data to another worksheet using the
provided export options. In this way the user avoids making edits to the master Excel
viewer file which is extremely sensitive to the existing format.

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3.2.1 Haze Chart Description

The first option for the user is to calculate and view a “Haze Chart”. The haze chart
allows the user to view elevations, inflows or outflows for a particular plant for the
scenario. The plot is designed to give the user an understanding of how the plant is
operating on a annual scale. The haze chart answers questions like: How far does the
reservoir get drawn down each year? How much volume is being carried over from year
to year? How different are the inflows and discharges between dry and wet years?

To calculate a haze chart, click on the “View Haze Chart” button. The model will open
up a dialog that allows the user to select which plant and what type of data the user would
like to see. The model will then calculate the haze chart and show the chart to the user as
shown in Figure 3-36. The user can export the chart and chart data to another
spreadsheet or return to the main interface. To view charts from another scenario, the
user must load a different scenario by click on the “Load Scenario Data” button.

Figure 3-36 Haze Chart

3.2.2 Annual Details Plot

Clicking on the “View Details Chart” button as shown below in Figure 3-37 retrieves the
annual details plot. The plot is an annual plot of inflow, turbine discharge, total plant
outflow, and reservoir elevation. This chart allows the user to review how the model is
operating the plant on a daily and seasonal basis.

Figure 3-37 Annual Details Plot

When the user clicks on the “View Details Chart” button an interface will open where the
user can select which plant and which year to view. The user must “Load Scenario Data”
if the user would like to see data from a different scenario.

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3.2.3 Duration Curve Description

The durations curve option allows the user to create and view duration or exceedence
curves similar to the one shown below in Figure 3-38. The user has the option to view
curves of the inflows, outflows and elevations. The user can view curves that are made
up of data from one year, the period of record, or a curve made up of data from a given
month from all the years. For example the user can view an inflow duration curve for
1985, a duration curve for the inflows from 1982 to 1996 if the run period was 1982 to
1996 or the duration curve for all the inflows in March between 1982 and 1996.

Figure 3-38 Duration Curve

When the user clicks on the “View Duration Curves” button the model will ask the user
which plant, which type of data (inflows, outflows, elevations) and what time range the
user would like. The model will then load the output data and display a chart.

3.3 DETAILED OUTPUT VIEWER INTERFACE

Like the Rule Curve output viewer the Detailed Output Viewer is an Excel file located in
the Output folder in the CHEOPS™ model directory. The file is called “Details.xls” and
should be opened from the main CHEOPS™ interface. The model will load into the file
the current model scenarios and other pertinent information. The details viewer main
interface is shown below in Figure 3-39.

Figure 3-39 Details Output Viewer Main Interface

The first step for the user is to click on the “Load Choices” button. This button allows
the model to check the output files to check for years and data completeness.

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The “Display Details” button will open another interface where the user can specify what
detailed chart the user wants to view. The user selects the scenario, plant, First Day of
the plot and the number of days to be included in one plot. With the user’s preferences
have been selected, click on the “Load Data” button and the model will open the output
files and display the detailed model output in a chart similar to the one below in Figure 3-
40.

Figure 3-40 Details Plot

The user can scroll through the days of each year by using the next day and previous day
buttons at the top of the plot. It view another plant, scenario or year the user must return
to the main interface. The detailed data is quite extensive and the output viewer can only
load a single year of one plant’s output data at one time.

These plots allow the user to review how the model is operating the system on a 15-
minute basis. The user can see how the model steps up generation during the peak period
and how the model operates differently on weekends vs. weekdays. The plot data can be
viewed and manipulated by exporting the chart to another spreadsheet.

3.4 ENERGY OUTPUT VIEWER INTERFACE

The energy output viewer is an Excel file named “Energy Output.xls” and is shown
below in Figure 3-41. Similar to the other two output viewers the user must first load the
scenario choices. This routine checks the output files for which years are included. The
next stage is for the user to click on the “Load Scenario Data” button. The user will then
select a scenario and the model will load the tabulate the generation (MWh) and benefits
($) for that scenario.

Figure 3-41 Energy Output Viewer

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3.4.1 View Monthly Results

After the user has loaded the scenario data and the viewer has tabulated the output data
the user can view the data by year. Clicking on the “View Monthly Results” button will
open a new tab for each year in the run. A sample year sheet is shown below in Figure 3-
42.

Figure 3-42 Sample Energy Year Sheet

As shown above each sheet contains summaries of generation and benefits by
powerhouse by period by month. At the far right side of the worksheet the user will find a
system wide summarization.
3.4.2 View Annual Benefits

The “View Annual Benefits” button opens up two sheets that allow the user to compare
how the powerhouses and system is changing operations from year to year. A sample of
the generation tab is shown below in Figure 3-43.

Figure 3-43 Annual Generation Benefits

This sheet shows the annual generation for each powerhouse by period for each year in
the run. This data can be used to check the sensitivity of changes to the system on year to
year basis, allowing the user to examine both wet year and dry year impacts.