EtapCh29 OCP

7/27/2019 EtapCh29 OCP

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Chapter 29

Optimal Capacitor Placement

Most power systems that operate at a lagging power factor due to loads and delivery apparatus(lines and transformers) are inductive in nature. Therefore, power systems require additional varflow. This results in reduced system capacity, increased losses and decreased voltage.

According to IEEE Standard 1036-1992 (IEEE Guide for Application of Shunt PowerCapacitors), the purposes of shunt capacitor applications are:

Purpose Benefits

Var support This yields a primary benefit for transmission systems and asecondary benefit for distribution systems.

Voltage control This yields a primary benefit for both transmission anddistribution systems.

System capacity increase This yields a secondary benefit for transmission systems anda primary benefit for distribution systems.

System power loss reduction This yields a secondary benefit for transmission systems anda primary benefit for distribution systems.

Billing charge reduction This does not apply to transmission systems but yields aprimary benefit for distribution systems.

To place shunt capacitors in power systems, you must perform the following tasks:

Determine the bank size in kvar

Determine the connection location

Determine a control method

Determine a connection type (wye or delta)

You can determine the capacitor size and the proper location for voltage support and power factorcorrection in different ways. One common method is based on applying rules of thumbtechniques, followed by running multiple load flow studies for fine-tuning the size and location.

Operation Technology, Inc. 29-1 ETAP 5.0 User Guide


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Optimal Capacitor Placement Overview

This method may not yield the optimal solution. It can also be very time consuming andimpractical for large systems.

Minimizing the cost while determining the capacitor size and location mathematically is anoptimization problem. Therefore, you should employ an optimization approach. The ETAPOptimal Capacitor Placement (OCP) module is an extremely powerful simulation tool that is

specifically designed for this application. The OCP module helps you place capacitors for voltagesupport and power factor correction while minimizing total cost. The advanced graphicalinterface gives you the flexibility to control the capacitor placement process and allows you toview the results graphically. The precise calculation approach automatically determines the bestlocation and bank sizes. In addition, it reports the branch capacity release and the savings duringthe planning period due to var loss reduction.

The capabilities of the OCP module are summarized below:

Key Features

Best location and bank sizeMinimum total installation and operation cost

Voltage support and power factor correctionCapacitor control methodReview capacitor impact on the system

Flexible OperationAvailable locationsSelectable capacitor typesDifferent load categoriesMultiple cost functionsUser selectable objectivesFlexible constraints

CapabilityAdvanced graphical user interfaceUser friendly input and outputGraphically view new capacitorsRadial or meshed networksSpeed and precision controlIntegrated load flow resultsStandard Crystal Reports

PlottingLoss reduction savings during the planning periodCapacitor operation cost during the planning period

Profit during the planning period

ReportingCapacitor propertiesCapacitor locations and sizesLoad flow results for maximum, average and minimum loadsBranch capacity releaseCost summary



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Optimal Capacitor Placement Study Toolbar

29.1 Study Toolbar

The Optimal Capacitor Placement toolbar appears when you are in the Optimal CapacitorPlacement mode. The toolbar has seven command buttons, as shown below.

Run Optimal Capacitor Placement

Display Options

Alert View

Report Manager

Optimal Capacitor Placement Plots

Halt Current Calculation

Get On-Line Data

Get Archived Data

29.1.1 Run Optimal Capacitor PlacementTo run an optimal capacitor placement calculation, do the following:

1. Select and edit a study case from the Study Case toolbar when you are in OptimalCapacitor Placement mode.

2. Click the Run Optimal Capacitor Placement button to perform the optimal capacitorplacement.

A dialog box appears that allows you to specify the output report name if the Output FileName is set to Prompt in the Output Report list box. The optimal capacitor placement resultscan be viewed in the one-line diagram display, in the output report tabulated formats, and inthe plot formats.

29.1.2 Display OptionsTo customize the OCP one-line diagram annotation display options, do the following:

1. Click the Display Options button. For more information, see Section 23.4, DisplayOptions.

Note: You must be in Optimal Capacitor Placement mode.



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29.1.3 Alert ViewThe Alert View button is not enabled for this release.

29.1.4 Report Manager

To open the OCP Report Manager, do the following:

1. Click the Report Manager button to display the OCP Report Manager. Here you canselect a variety of pre-formatted output files.

2. Click the Result page.3. Select a file type.4. Click OK to display the output report.

For a detailed explanation of the OCP Report Manager, see Section 23.7, Output Reports.

You can also select output files from the Output Report list box.

This list contains all the output report files in the current project folder.



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Optimal Capacitor Placement Plots

To view optimal capacitor placement plots, do the following:

1. Click the Optimal Capacitor Placement Plots button. The Capacitor Placement PlotSelection dialog box appears.

2. Select the combinations of plots you want to view, including Loss Reduction SavingDuring Planning Period, Capacitor Operation Cost During Planning Period, and ProfitDuring Planning Period.

Halt Current Calculation

To stop the current optimal capacitor placement calculation, do the following:

1. Click the Halt Current Calculation button (contains the red circle with X icon).

Note: The Halt Current Calculation button is normally disabled. When you start an optimalcapacitor placement calculation, this button becomes enabled and appears as a button with a redcircled X icon. If you terminate the calculation before it completes, one-line diagram displays will

not be available and the output report will be incomplete.

Get On-Line Data

This button is reserved for the on-line Real-Time module.

Get Archived Data

This button is reserved for the on-line Real-Time module.



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Optimal Capacitor Placement Study Case Editor

29.2 Study Case EditorThe Optimal Capacitor Placement (OCP) Study Case editor contains solution control variables.ETAP allows you to create and save an unlimited number of study cases for each type of study.Like any other study types, you can switch between different OCP study cases. This feature isdesigned to organize your study efforts and save you time.

You can use a study case for any combination of configuration status, one-line diagrampresentation, and base/revision data.

The Capacitor Placement Study Case editor consists of six pages:

Info pageLoading pageBus kV Constraint pagePower Factor Constraint pageCapacitor pageAdjustment page

To Create a New OCP Study Case

1. Go to the Project View.2. Right-click on the Capacitor Placement subfolder inside the Study Case folder, and select

Create New.

The module creates a new study case, which is a copy of the default study case. You can addthis to the Capacitor Placement subfolder. You can also create a new study case by using theNew button on the OCP Study Case toolbar.



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When you are in the Optimal Capacitor Placement mode, you can access the Capacitor PlacementStudy Case editor by clicking the Edit Study Case button on the Study Case toolbar. You can alsoaccess this editor from the Project View by clicking the Capacitor Placement subfolder under theStudy Case folder.

29.2.1 Info PageThe Info page of the Capacitor Placement Study Case editor allows you to specify some generalsolution parameters and study case information.

Study Case ID

The study case ID is shown in this text box. You can rename a study case by deleting the old IDand entering a new ID. The study case ID is limited to 25 alphanumeric characters. Use the arrowbuttons at the bottom-right of the editor to go from one study case to another.



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Objective

In the Objective group, you can select the capacitor placement objective. The objective allows theOCP module to place capacitors to perform voltage support, power factor correction, or both atthe same time.

Voltage SupportIf you select this option, the OCP module checks only voltage limits and places capacitors tomeet the voltage limits when minimizing the cost.

Power Factor CorrectionIf you select this option, the OCP module checks only load power factor limits and placescapacitors to meet the load power factor limits when minimizing the cost.

BothIf you select this option, the OCP module checks both voltage limits and load power factor limitsand places capacitors to meet both the voltage limits and load power factor limits whenminimizing the cost.

Load Flow Parameter

In this group you can set parameters for load flow calculations with which to control load flowsolutions.

Max. IterationEnter the maximum number of iterations to attempt convergence. If the solution does notconverge before the specified number of iterations, the load flow calculation stops.

If the attempted solution is for initial load flow calculations, the OCP module will inform you.However, during the capacitor placement process, the OCP module abandons the solutionbecause this is not a reasonable capacitor placement result.

PrecisionEnter the value for load flow solution precision. The OCP module uses this value to check forconvergence.

For more information, see Chapter 15, Load Flow Analysis.

Precision / Speed Ratio

Move the slider to adjust the precision to speed ratio of the OCP study case. Precision and speedare linked inversely. While the speed setting increases from 1 to 10, the precision settingdecreases from 10 to 1. The upper value shows the current speed setting. The lower value showsthe current precision setting. Position the slider to the left to get the optimal solution. Moving theslider to the right will speed up the solution but may yield a less than optimal result.

General Parameter

In the General Parameter group, you can specify cost and control parameters.

Source Energy CostIf you select this option, the energy cost in $/kWh will be calculated from the generation sources.



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See the Energy Cost pages of Power Grid and Generator in Chapter 8, AC Elements.

Average Energy CostIf you enable this option, an average energy cost value will be used.

Cost

Enter the value for average energy cost ($/kWh) in the Cost text box.

Planning Period

Enter the period (years) when you intend to get maximum benefit by installing capacitors. TheOCP module analyzes the cost, saving, and profit during these years.

Interest Rate

Enter the interest rate (%/year) that you want to use to calculate the cost, saving, and profit byyears.

Note: A fixed 3% inflation rate is considered in the cost calculation.

Apply XFMR Phase-Shift

Enable this option to consider transformer phase-shift in load flow calculations. The phase-shiftof a transformer can be found from the transformer editor.

Initial Condition

Initial conditions for all bus voltages and angles can be specified in this section for calculationpurposes.

Use Bus VoltagesSelect this option to use bus voltages and angles as entered on the Info page of the bus editors.Using this option, you can simulate OCP studies with different initial conditions for bus voltage.

Use Fixed ValueThis option allows you to simulate OCP studies using a fixed bus voltage and angle for all buses.When you select the fixed initial condition option, you must enter the initial voltage value as thepercent of the bus nominal voltage. The default values are 100% for bus voltage magnitude andzero degree for bus voltage angle.

Study Remarks

You can annotate your output pages in the Study Remarks group. Enter up to 120 alphanumericcharacters in the text box. The information you enter here will be printed on the second line ofevery output page header line. These remarks can provide specific information for each study

case.

Note: The first line of the header information is global for all study cases and is entered in theProject Information editor.



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29.2.2 Loading PageThe Loading page allows you to specify the system loading information.

Loading Category

In the Loading Category group of the OCP Study Case editor, you can specify the operating loadsby selecting a loading category.

Average LoadSelect one of the ten loading categories from the Average Load drop-down list for the OCP studycase. For any category you select, ETAP uses the percent loading of individual motors and otherloads as specified for the selected category.



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Note: You can assign loading to each one of the ten categories from the Nameplate page of theInduction Machine editor and Synchronous Motor editor and from the Loading or Rating page ofother load component editors.

Operating P, QThis option is available if your ETAP installation has the Real-Time module. When you select

this box, the operating loads upload from on-line data or a previous load flow study is utilized inthe load flow study.

Generation Category

Generation CategorySelect one of the ten generation categories for the OCP study case. For more information, seeChapter 15, Load Flow Analysis.

Operating P, Q, VThis option is available if your ETAP installation has the Real-Time module. When you selectthis box, the operating loads upload from on-line data or a previous load flow study is utilized inthe load flow study.

Charger Loading

For chargers, you have the option to use the loading category load or the operating load.

Note: The operating load for a charger can only be updated from a DC load flow study.

Load Diversity Factor

This group allows you to specify load diversity factors to be applied on the loading category load.

Individual Bus Min. & Max.

When you select this option, the OCP module uses the individual bus load diversity factor thatyou specified for each bus. For more information, see the descriptions of the Bus editor in Section8.1, Bus.

GlobalWhen you select this option, the OCP module uses a global load diversity factor for all buses.Enter the maximum and minimum global load diversity factor in percentage.

Load Duration (Hours / Year)

Enter the load duration for maximum and minimum load in percent hours per year. The hour foraverage load is calculated, since the total hour percentage is 100.

Note: You can use the load duration to investigate capacitor placement effects on a power system.When the maximum load duration is not zero, OCP places capacitors to meet maximum loadrequirement and display load flow results for maximum load. OCP outputs load flow results forminimum and average load as well. If maximum load duration is zero, OCP places capacitors tomeet average load requirement. OCP displays load flow results for average load and output reportfor minimum and maximum load as well. If load durations for both maximum and minimumloads are zero, OCP places capacitors to meet the minimum load requirement and display loadflow results for minimum load.



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Example for Using Load Duration to Investigate Capacitor Placement EffectYou may set the load duration for minimum load to 100 so that OCP finds the fixed capacitorbanks and sizes for minimum load conditions. Then, you may set the actual load durations formaximum, minimum, and average loads to find the switched capacitor banks for load levelsabove the minimum condition up to peak load.

29.2.3 Voltage ConstraintThe Voltage Constraint page allows you to specify the bus kV constraints.

General Constraint

This group allows you to specify general voltage constraints for maximum and minimumvoltages.



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General ConstraintWhen you select General Constraint, you can enter the percentage values for maximum andminimum voltages.

Maximum VoltageThe Maximum Voltage is the global limit (in percent) for the maximum voltage of all buses,

except the ones selected for the Individual Constraint list.

Minimum VoltageThe Minimum Voltage is the global limit (in percent) for the minimum voltage of all buses,except the ones selected for the Individual Constraint list.

Individual Constraint

This group displays information on all the selected buses, including the Bus ID, kV rating, andmaximum and minimum voltage. The global constraint does not apply to these buses.

Select/Deselect Buttons

1. Highlight a bus from the list box underneath the buttons.This box initially lists all the buses in the system for the specified Available Bus option.2. Click the Select button to move the highlighted bus into the Individual Constraint box.

Note: Highlighting a bus in the Individual Constraint box and clicking the Deselect buttonmoves that bus into the list box underneath the button to let the bus use global constraints.

Available BusIn this group you specify which of the available buses to show.

All

Show all the buses in the system.

High Voltage

Show all the buses in the system whose rated voltage is higher than 1 kV.

Low Voltage

Show all the buses in the system whose rated voltage is equal to or lower than 1 kV.

Include Nodes

Check this box to include nodes as buses.

Default SettingsThis group sets the voltage limits for the buses that you select for the Individual Constraint list.

Max. Voltage

This option sets the maximum voltage limit in percent.

Min. Voltage

This option sets the minimum voltage limit in percent.



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29.2.4 Power Factor ConstraintThe Power Factor Constraint page allows you to specify the bus power factor constraints.

Allow Over Compensation

If you select this option, the OCP module may place capacitors to supply reactive power that ismore than the loads reactive power demand at that bus, when it is economically justified. When

you select this option, the maximum power factor constraint is not applied.

General Constraint

This group allows you to specify general constraints for maximum and minimum power factor.When you select General Constraint, you can enter the values for maximum and minimum powerfactors.



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Max. PFThe maximum power factor is the global limit for the maximum power factor of all buses, exceptthe ones selected for the Individual Constraint list. Max Power Factor is not available when youenable Allow Over Compensation.

Min. PF

Min Power Factor is the global limit for the minimum power factor of all buses, except the onesselected for the Individual Constraint list.

Individual Constraint

This box lists information about all the selected buses, including the Bus ID, kV rating, andmaximum and minimum power factor in percentage. The global constraint does not apply to thesebuses.

Select/Deselect Buttons1. Highlight a bus from the box underneath the buttons.

This box initially lists all the buses in the system for the specified Available Bus option.

2. Click the Select button to move the highlighted bus into the Individual Constraint box.

Note: Highlighting a bus in the Individual Constraint box and clicking the Deselect buttonmoves that bus into the box underneath the button so that the bus uses global constraints.

Available BusIn this group you specify which of the available buses to show.

All

Shows all the buses in the system.

High Voltage

Shows all the buses in the system whose rated voltage is higher than 1 kV.

Low Voltage

Shows all the buses in the system whose rated voltage is equal to or lower than 1 kV.

Include Nodes

Select this box to include nodes as buses.

Default SettingsThis group allows you to specify the power factor limits for the buses which will be selected forthe Individual Constraint list.

Max. PF

Specify the maximum power factor limit (in percent).

Min. PF

Specify the minimum power factor limit (in percent).



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29.2.5 CapacitorThis page allows you to specify the capacitor information.

Capacitor Info

This group allows you to specify capacitor related information. Each row gives the informationfor one kind of capacitor.

Max. kVEnter the maximum possible rated voltage level (in kV) to which this kind of capacitor can beused.

Bank Size (kvar)Enter the bank size in kvar for this kind of capacitor.



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Max#BanksEnter the maximum number of banks that can be installed at a bus that uses this kind of capacitor.

Purchase ($/kvar)Enter the purchase cost in $/kvar for this kind of capacitor.

Note: The purchase cost will be paid off with its interest during the planning period.

Install ($)Enter the installation cost for installing this kind of capacitor.

Note: The installation cost will be paid off with its interest during the planning period.

Operating ($/BankYr)Enter the operating cost in $ per bank, per year, for this kind of capacitor.

Note: The cost is for the current year and a 3% per year inflation is considered during theplanning period.

Bus Candidates

BusesShows all the available buses in the Bus Category option.

Bus Category

All Buses Shows all the buses in the system.

HV Buses Shows all the buses in the system whose rated voltage is higher than1 kV.

LV Buses Shows all the buses in the system whose rated voltage is equal to orlower than 1 kV.

HV SWGR Shows all the switchgear buses in the system whose rated voltage ishigher than 1 kV.

LV SWGR/MCC Shows all the switchgear and MCC buses in the system whose ratedvoltage is equal to or lower than 1 kV.

CandidatesLists all the candidates to install capacitors.

Note: Use the Add and Remove buttons to add or remove bus candidates.



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29.2.6 AdjustmentThe page allows you to specify the adjustment. Adjustments are for load flow study.




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Optimal Capacitor Placement Display Options

29.3 Display Options

29.3.1 Results Page

The Optimal Capacitor Placement (OCP) Display Options editor consists of a Results page andthree pages for AC, AC-DC, and DC information annotations.

Note: The colors and displayed annotations selected for each study are specific to that study.

Color

Select the color for displaying result annotations on the one-line diagram.



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Show Units

Select this option to show units for displaying power flow and current on the one-line diagram.

Check All

Select this option to show all available result annotations.

Note: When this box is cleared, the previous settings are restored.

Voltage

VoltageFrom the list, Select kV or percent for displaying voltage on the one-line diagram.

Bus Mag.Select this option to display bus voltages on the one-line diagram.

Note: Bus voltages are displayed at 15 degrees.

Bus AngleSelect this option to display bus angle (in degrees) on the one-line diagram.

Note: Bus voltage angles are displayed at -15 degrees.

Load Term. Mag.Select this option to display load (motors, lump loads, and static loads) terminal voltages on theone-line diagram.

Note: Load terminal voltages are displayed at 15 degrees. You can display load terminal voltagesbased on load rated kV or bus nominal kV, depending on the selection in Load Term. Base kV.

Load Term. Base kV

This group allows you to select base kV for load terminal magnitude, when you select the voltageto be displayed in percent.

Note: This group will be disabled if you selected kV for the voltage display.

Load Rated kVSelect this option to use load rated kV as the base for load terminal voltage display.

Bus Nom. kV

Select this option to use bus nominal kV as the base for load terminal voltage display.

Voltage Drop

Line / CableSelect this option to display line and cable voltage drops on the one-line diagram.

Load FDRSelect a unit for power flow or current flow from the list to be displayed on the one-line diagram.



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Power Flows

This group allows you to specify how the flows are displayed.

UnitsSelect the unit (kVA or MVA) to be used to display power flow on the one-line diagram.

kW + jkvarSelect the kW + jkvar option to display power flow in kW+jkvar or MW+jMvar.

kVASelect the kVA option to display power flow in kVA or MVA.

AmpSelect the Amp option to display current flow in amperes.

%PFWhen you select either the Amp or kVA option, you can select this option to show the power

factor of power flow along with the current.

Flow Results

BranchSelect this option to display power flow through all branches on the one-line diagram. ETAPdisplays the power flow at one end of a branch (the end that has a positive kW value flowing intothe branch). For 3-winding transformers, all three power flows are displayed.

SourceSelect this option to display power flow for generators and power grids on the one-line diagram.

LoadSelect this option to display power flow for motors, MOVs, capacitors, lumped loads, and staticloads on the one-line diagram.

Composite MotorSelect this option to display power flow into composite motors.

Composite NetworkSelect this option to display power flow into composite networks.



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Panel SystemSelect this option to display results for panel systems on the one-line diagram, assuming youselected the Calc. Panel System option in the study case when the load flow calculation wasperformed.

Note: If you did not enable the Calc. Panel System option in the load flow study case, or you didnot enable the Panel System display option, no result will be displayed on the one-line diagram.

Panel Systems


Branch Losses

Select this option to display branch losses on the one-line diagram.

Note: Losses are displayed inside a bracket in [kW+jkvar] or [MW+jMvar].

Meters

AmmeterSelect this option to display primary current for the branch to which an ammeter is attached.

VoltmeterSelect this option to display primary voltage for the bus to which a voltmeter is attached.

Multi-MeterSelect this option to display the measurements of a multi-meter, including bus voltage, branchcurrent, branch power flow, power factor, and frequency.

29.3.2 AC Page

This page allows you to specify options for displaying information annotations for AC elements.



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ColorSelect the color for displaying information annotations on the one-line diagram.

IDSelect the check boxes under this heading to display the ID of the selected AC elements on theone-line diagram.

RatingSelect the check boxes under this heading to display the ratings of the selected AC elements onthe one-line diagram.

Device Type Rating

Generator kW / MW

Power Grid (Utility) MVAsc

Motor HP / kW

Load / Panel kVA / MVA and connection type ( # of phases - # of wires)

Transformer kVA / MVA

Branch, Impedance Base MVA



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Device Type Rating

Branch, Reactor Continuous amps

Cable / Line # of cables - # of conductor / cable - size

Bus kA bracing

Node Bus bracing (kA)

CB Rated interrupting (kA)

Fuse Interrupting (ka)

Relay 50/51 for over-current relays

PT & CT Transformer rated turn ratio

kVSelect the check boxes under this heading to display the rated or nominal voltages of the selectedelements on the one-line diagram.

Note: For cables/lines, the kV check box is replaced by the T button. Click this button to display

the cable/line conductor type on the one-line diagram.

ASelect the check boxes under this heading to display the ampere ratings (continuous or full-loadampere) of the selected elements on the one-line diagram.

Note: For cables/lines, the Amp check box is replaced by the L button. Click this button todisplay the cable/line length on the one-line diagram.

ZSelect the check boxes under this heading to display the rated impedance of the selected ACelements on the one-line diagram.

Device Type Impedance

Generator Subtransient reactance Xd"

Power Grid (Utility) Positive sequence impedance in % of 100 MVA (R + j X)

Motor % LRC

Transformer Positive sequence impedance (R + j X per unit length)

Branch, Impedance Impedance in ohms or %

Branch, Reactor Impedance in ohms

Cable / Line Positive sequence impedance (R + j X in ohms or per unit length)

D-YSelect the check boxes under this heading to display the connection types of the selected elementson the one-line diagram.

For transformers, the operating tap settings for primary, secondary, and tertiary windings are alsodisplayed. The operating tap setting consists of the fixed taps plus the tap position of the LTC.



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Composite MtrSelect this option to display the AC composite motor IDs on the one-line diagram, then select thecolor for displaying the IDs.

Use Default OptionsSelect this option to use ETAPs Default Display Options.

29.3.3 AC-DC Page

This page allows you to specify display options for information annotations for AC-DC elementsand composite networks.




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IDSelect the check boxes under this heading to display the IDs of the selected AC-DC elements onthe one-line diagram.

RatingSelect the check boxes under this heading to display the ratings of the selected AC-DC elements

on the one-line diagram.

Device Type Rating

Charger AC kVA & DC kW (or MVA / MW)Inverter DC kW & AC kVA (or MW / MVA)UPS kVAVFD HP / kW

kVSelect the check boxes under this heading to display the rated or nominal voltages of the selectedelements on the one-line diagram.

ASelect the check boxes under this heading to display the ampere ratings of the selected elementson the one-line diagram.

Device Type Amp

Charger AC FLA & DC FLAInverter DC FLA & AC FLAUPS Input, output, & DC FLA

Composite NetworkSelect this option to display the composite network IDs on the one-line diagram, then select thecolor for displaying the IDs.

Use Default OptionsSelect this option to use ETAPs default display options.

29.3.4 DC Page

This page allows you to specify options for displaying information annotations for DC elements.



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IDSelect the check boxes under this heading to display the IDs of the selected DC elements on theone-line diagram.

RatingSelect the check boxes under this heading to display the ratings of the selected DC elements onthe one-line diagram.



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Device Type Rating

Battery Ampere hourMotor HP / kWLoad kW / MWElementary Diag. kW / MW

Converter kW / MWCable # of cables - # of conductor / cable size

VSelect the check boxes under this heading to display the rated or nominal voltages of the selectedelements on the one-line diagram.

For cables, the V check box is replaced by the T button. Click this button to display the conductortype on the one-line diagram.

A

Select the check boxes under this heading to display the ampere ratings of the selected elementson the one-line diagram.

For cables, the Amp check box is replaced by the L button. Click this button to display the cablelength (one way) on the one-line diagram.

ZSelect the check boxes under this heading to display the impedance values of the cables andimpedance branches on the one-line diagram.

Composite MtrSelect this option to display the DC composite motor IDs on the one-line diagram, then select the

color for displaying the IDs.

Use Default OptionsSelect this option to use ETAPs default display options.



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Optimal Capacitor Placement Calculation Method

29.4 Calculation Method

ETAP currently utilizes the genetic algorithm for optimal capacitor placement. The geneticalgorithm is an optimization technique based on the theory of natural selection.. A geneticalgorithm starts with a generation of solutions with wide diversity to represent characteristics of

the whole search space. By mutation and crossover, good characteristics are selected and carriedto the next generation. The optimal solution can be reached through generations.

OCP uses the present worth method to perform alternative comparisons. It considers initialinstallation and operating costs, which include maintenance, depreciation, and loss reductionsavings. It also provides interest rate and inflation consideration.

29.4.1 Objective Function of OCPThe objective of optimal capacitor placement is to minimize the cost of the system. The costincludes four parts:

fixed capacitor installation costcapacitor purchase costcapacitor bank operating cost (maintenance and depreciation)cost of real power losses

The cost can be represented mathematically as:

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$/kWhinloss,kWheachofCost-2



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Optimal Capacitor Placement Calculation Method

29.4.2 ConstraintsThe main constraints for capacitor placement are used to meet the load flow constraints. Inaddition, all voltage magnitudes of load (PQ) buses should be within the lower and upper bars.Power Factor (PF) should be greater than the minimum. It may be a maximum power factor bar.

The constraints can be represented mathematically as:

1) Load Flow: 0),( =uxF

2) VV busesPQallfor, maxminmaxmin PFPFPFV



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Optimal Capacitor Placement Required Data

29.5 Required Data

Bus Data

The data required for optimal capacitor placement (OCP) is the same as for load flowcalculations. For buses this includes:

Nominal kV%V and angle (when the Initial Condition option is set to Use Bus Voltages)Load diversity factor (when the Loading option is set to Use Bus Diversity Factor on theLoad page of the Study Case editor)

Branch Data

Branch data is entered into the branch editors (Transformer, Transmission Line, Cable, Reactor,and Impedance editors). The data required for OCP is the same as for load flow calculations. Forbranches this includes:

Branch Z, R, X, or X/R values and units, tolerance, and temperature, if applicableCable and transmission line, length, and unitTransformer rated kV and kVA/MVA, tap, and LTC settingsImpedance base kV and base kVA/MVA

Power Grid Data

The data required for OCP calculations includes:

Operating mode (Swing, Voltage Control, or Mvar Control)Nominal kV%V and angle for swing mode%V, MW loading, and Mvar limits (Qmax & Qmin) for voltage control mode of operation

MW and Mvar loading for Mvar control modeEnergy cost data (Min MW, Max MW, MW and $Cost Points, if the Use Source EnergyCost option is selected on the Info page of the Study Case editor)

Synchronous Generator Data

The data required for OCP calculations for synchronous generators includes:

Operating mode (Swing, Voltage Control or Mvar Control)Rated kV%V and angle for swing mode of operation%V, MW loading, and Mvar limits (Qmax & Qmin) for voltage control mode of operation

MW and Mvar loading for Mvar control mode of operationFuel cost data (Min MW, Max MW, Model Type, MW and $Cost Points, if the UseSource Energy Cost option is selected on the Info page of the Study Case editor)



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Inverter Data

The data required for OCP calculations for inverters includes:

Inverter ID

DC and AC rating dataAC output voltage regulating data

Synchronous Motor Data

The data required for OCP calculations for synchronous motors includes:

Rated kW/hp and kVPower factors and efficiencies at 100%, 75%, and 50% loadingsLoading category ID and % loadingEquipment cable data

Induction Motor Data

The data required for OCP calculations for induction motors includes:

Rated kW/hp and kVPower factors and efficiencies at 100%, 75%, and 50% loadingsLoading category ID and % loadingEquipment cable data

Static Load Data

The data required for OCP calculations for static loads includes:

Static load ID

Rated kVA/MVA and kVPower factorLoading category ID and % loadingEquipment cable data

Existing Capacitor Data


Capacitor IDRated kV, kvar/bank, and number of banksLoading category ID and % loadingEquipment cable data

Lumped Load Data


Load IDRated kV, MVA, power factor, and % motor loadLoading category ID and % loading



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Charger and UPS Data

The data required for OCP calculations for chargers and UPSs includes:

Element IDRated AC kV, MVA, and power factor, as well as DC rating data

Loading category ID and % loading

Other Data

There are some study case related data that must also be provided. See the Study Case editor forstudy case data requirements.

Note: On the Capacitor page, you must select bus candidates for the OCP module to runsuccessfully.



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Optimal Capacitor Placement Output Reports

29.6 Output Reports

The optimal capacitor placement calculation results are reported on the one-line diagram and inthe Crystal Reports format. The graphical one-line diagram displays the results of calculationssuch as bus voltages, branch flows and voltage drops, and load power consumption for maximum,

minimum, or average load.

Use the Display Options editor to specify the content you want to display. The one-line diagramflags abnormal operating conditions in different colors. These include overloaded cables andover- or under-voltage buses. The one-line diagram also displays new capacitor information,which includes the total number of banks, rated kV, rated kvar, operating kvar, and amps.

The Crystal Reports format provides you with reports containing detailed information aboutcapacitor installation and load flow analysis. You can use the OCP Report Manager to view theoutput report.

29.6.1 Crystal Reports format

View from Study Case Toolbar

The Study Case toolbar provides a shortcut for the OCP Report Manger options. When you clickthe List Output Reports button, ETAP automatically opens the List Output Report dialog box tothe output report listed in the Study Case toolbar with the selected format. In the example toolbarshown below, the output report name is OCP and the selected format is Cable.

Report Manager

To open the Report Manager, click the Report Manager button on the Optimal CapacitorPlacement toolbar. The OCP Report Manager includes four pages (Complete, Input, Result, andSummary) which represent different sections of the output report. The OCP Report Managerallows you to select from the listed formats for each section of the report. You can also view theOCP Report Manager using Crystal Reports. Several fields and buttons are common to everypage.

Output Report NameThis field displays the name of the output report you want to view.

PathThis field displays the name of the project file, based on which report was generated, along withthe directory where the project file is located.

HelpClick this button to access Help.



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OK / CancelClick OK to close the OCP Report Manager and display the Crystal Reports view. This shows theselected section of the output report.

Note: If you do not make a selection, the OCP Report Manager closes.

Click Cancel to close the OCP Report Manager without viewing the report.

Input Data

This page allows you to select different formats for viewing the input data. The input data isgrouped according to type:

AdjustmentsBranchBus ConstraintsBusCable

Capacitor Info DataCoverImpedanceReactorSVCTransformer

Sample 1: Input Data

This section lists system input parameters for buses, transmission lines and cables, transformers,reactors, impedances, and all connections including tie circuit breakers, fuses, and switches.



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Result

This page allows you to select different formats for viewing the result report. The formatsinclude:

LF Report AverageLF Report MaximumLF Report MinimumOCP Results

Sample 2: Load Flow ReportThis section of the report tabulates detailed load flow results. The results reported include:

Bus ID and nominal kVCalculated voltage magnitudes and anglesMW and Mvar generation and loading

Branch flows from the bus to all buses connected to it

Flows are given in MW and Mvar, amps, and %PF measured at the bus. Flows into 3-windingtransformers are indicated as flows from one of the bus windings to the other two bus windings(from Main Bus to Sub 2B and Sub 3).

The settings of tap-changing transformers are also indicated at buses to which a tap side isconnected. These tap settings include the fixed taps and results from the LTCs. Regulated(voltage-controlled) buses are flagged with an asterisk (*).

Load flow results are reported for average, maximum, and minimum loads.

Sample 3: OCP Results ReportThis section of the report tabulates capacitor placement results. The results reported include:

Bus IDNominal kVCalculated voltage magnitudes and anglesPower factor and capacitor bank information (capacitor rated kV, rated kvar per bank,total number of banks installed, installation cost, total purchase cost, and total operationcost)



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Summary

This page allows you to select different formats for viewing result summary report. They include:

Branch Capacity Release

Branch LoadingBus LoadingLossesOCP Cost SummarySummary

Sample 4: OCP Cost Summary ReportThis section of the report tabulates the system cost information. The information summarizes thecost for each year during the planning period. The costs include installation cost, operation cost,savings, and profit.

Note: The interest rate is considered for the calculation.



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Sample 5: Branch Capacity Release ReportBranch capacity release is the MVA difference of the branch before and after capacitors areinstalled.



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29.6.2 PlotsYou can plot three different curves:

Loss Reduction Saving During Planning Period ($)Capacitor Operation Cost During Planning Period ($)

Profit During Planning Period ($)

To plot report data, click the Plot button on the Optimal Capacitor Placement toolbar.

The Capacitor Placement Plot Selection dialog box appears. Here you may select anycombination of plots by selecting options.

Note: The interest rate is considered when generating the plots.

Loss Reduction Saving During Planning Period

This plot shows savings in dollars due to loss reduction vs. years. When interest is considered, theactual saving will increase as a function of time.



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Capacitor Operating Cost During Planning Period

This plot shows the operating cost in dollars vs. years. When interest is considered, the actual costwill increase as a function of time.



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Profit During Planning PeriodThis plot shows profit in dollars vs. years. The saving each year will be used to pay off theoperating cost and installation cost. Any unpaid dollars should be considered as fixed cost, whichis treated as installation cost for the following year.

A positive profit can be yielded when the loss reduction saving is bigger than the operating cost

for each year.

Note: The purpose of placing capacitors is entirely about making profit. Profit might be negativeduring the whole planning period for some systems.



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29.6.3 One-Line Diagram Display Reports

When OCP finishes capacitor installation, the Calculation in Progress dialog box disappears.Capacitor installation and load flow results are then displayed on the one-line diagram. The

loading condition depends on the load duration setting.

For more information, see Section 23.3.2, Loading page.

In the following example, one 4.16 kV, 200 kvar capacitor is installed at bus Sub 3.

Date post:	14-Apr-2018
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EtapCh29 OCP

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