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Template: Overlay Setup

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Template version: v1

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Software required:

PSS®E
PowerFactory
PSCAD™
Preview of template's gridmo Flow showing Nodes

How to add this template to your project

  1. From within your gridmo project, open the flow dropdown and select 'Add flow'.
  2. Select the template you want to use and click 'Add to project'.

screenshot of the gridmo web app adding a flow to a project

Background​

Overlaying real-world data with simulation results is a crucial part of ensuring generator compliance and model accuracy. Real-world data may come from Hardware-in-the-Loop (HIL) testing, generator commissioning or generator operations monitoring. Typically, a number of standard tests are performed to assess a generator's performance and model accuracy. This template provides examples of the type of tests that may be performed, as well as demonstrating how to use gridmo's Overlay builder tool to overlay real-world data with simulation results.

A sample test procedure has been provided for the following type of tests:

  • Active power control - Pref changes
  • Reactive power control - Qref changes
  • Voltage control - Vref changes
  • Power factor control - PFref changes
  • Transformer tap position change
  • Frequency secondary injection (via playback)
  • Plant capacitor switching event
  • Network capacitor switching event
  • Network fault event (via playback)
  • Network switching event

In addition to overlays of real-world data with simulation results for the above tests, the template also contains pre-test simulations which are commonly used to demonstrate the predicted generator performance for each test prior to site testing.

tip
  • For Australian projects, the sample test procedure outlined in this template is a possible example of the tests conducted at one hold point level. This template may be used more than once for multiple hold points.
  • For each type of test, it is common to prepare different tests with varying steps/scenarios (i.e. varying active power step sizes). For simplicity, we have demonstrated a few examples but you may wish to add more tests depending on your test plan.
tip

By default, this template does not have subplot commands configured within Overlay builder. You may wish to add these for your tests and requirements in the Overlay builder window:

subplot commands in overlay builder window

Reference​

Common assumptions​

  • For a majority of tests, we have assumed the active power generation level to be 90% (or 0.9 [p.u.]) of the project rated active power [MW].
  • The pre-test simulations are conducted at the initial operating conditions as per the sample test procedure in the sections below. However, note that the simulation results will use the initial operating conditions as per the network conditions during the testing. This is reflected in the sample data where the initial operating conditions purposefully do not match with the pre-test simulations.
  • We assume that all real-world data is in a file format which is supported by the Data Node (i.e. .csv or .xlsx). If you have data which is in other formats (e.g. .pqzip), please convert the data into either .csv or .xlsx before using this template.
  • This template uses the Global Variables $site_scr and $site_xr to set the Thévenin equivalent representation of the network conditions. As the SCR and X/R ratio will be dependent on the network configuration on the day of site testing, users will have to calculate these values using the real-world data. This can be done by completing calibration Pref and Qref tests, observing the subsequent changes in Vpoc and back calculating the SCR and X/R ratio. Alternatively, you can use the following gridmo example: How to find the SCR of real-world data.

Active power control - Pref changes​

The purpose of these tests is to confirm your generating system's active power control capability. The table below outlines the sample test procedure, as well as the operating conditions under which the pre-test simulation is conducted.

DescriptionProcedurePre-test simulation initial conditionsData file name
VpocPpocQpocSCRX/R
Pref step of -20% (of Pmax)
  1. Ensure the following conditions before performing the test:
    • The generating system's output is above 90% of its maximum active power capacity.
    • The generating system is in its default reactive power control mode (e.g. voltage control mode), and any dynamic and static reactive support devices are in service.
    • The generating system transformer is under auto control.
    • The generating units are under park dispatch control.
  2. Confirm measurement systems are ready.
  3. Allow at least 10 seconds of recording time before applying a step.
  4. Apply a -20% (-0.2 pu) step to the active power reference setpoint.
  5. Wait until the response settles.
  6. Apply a +20% (+0.2 pu) step to the active power reference setpoint to return to the pre-test active power level.
  7. Wait until the response settles.
  8. View the test data file to ensure it has been successfully saved.
Default POC voltage90% of Pmax0Normal SCRNormal X/RWECCsolar_Pstep_HPX_SFPFT_LOC.xlsx
Pref step of +20% (of Pmax)Default POC voltage70% of Pmax0Normal SCRNormal X/R

tip

As active power steps can take a significant amount of time in real-world data due to low gains and/or ramp rate limits, we have split one test into two overlays (i.e. there are two tests using one data file which contains both the -20% step down and the +20% step up to pre-test level). You can do this for any type of test by creating multiple tests within Overlay builder, loading the same file twice, then analyzing a different section of data.

Reactive power control - Qref changes​

The purpose of these tests is to confirm your generating system's reactive power control capability. The table below outlines the sample test procedure, as well as the operating conditions under which the pre-test simulation is conducted.

DescriptionProcedurePre-test simulation initial conditionsData file name
VpocPpocQpocSCRX/R
Qref step of +25% (of reactive power capability) and return to 0 MVAr
  1. Ensure the following conditions before performing the test:
    • The generating system's output is above 90% of its maximum active power capacity.
    • The generating system is in reactive power control mode.
    • All reactive support plants/devices are offline.
    • The generating system transformer is under auto control.
    • The generating units are under park dispatch control.
    • The reactive power reference setpoint (Qref) is set such that the reactive power at the generating system's regulating points is 0 MVAr (i.e. Qpoc = 0).
  2. Confirm measurement systems are ready.
  3. Allow at least 10 seconds of recording time before applying a step.
  4. Apply a +25% step (of reactive power capability) to the reactive power reference setpoint.
  5. Wait until the response settles.
  6. Return the reactive power reference setpoint to 0 MVAr.
  7. Wait until the response settles.
  8. View the test data file to ensure it has been successfully saved.
Default POC voltage90% of Pmax0Normal SCRNormal X/RWECCsolar_Qstep1_HPX_SFRPT.xlsx
Qref step of -25% (of reactive power capability) and return to 0 MVAr
  1. Ensure the following conditions before performing the test:
    • The generating system's output is above 90% of its maximum active power capacity.
    • The generating system is in reactive power control mode.
    • All reactive support plants/devices are offline.
    • The generating system transformer is under auto control.
    • The generating units are under park dispatch control.
    • The reactive power reference setpoint (Qref) is set such that the reactive power at the generating system's regulating points is 0 MVAr (i.e. Qpoc = 0).
  2. Confirm measurement systems are ready.
  3. Allow at least 10 seconds of recording time before applying a step.
  4. Apply a -25% (of reactive power capability) step to the reactive power reference setpoint.
  5. Wait until the response settles.
  6. Return the reactive power reference setpoint to 0 MVAr.
  7. Wait until the response settles.
  8. View the test data file to ensure it has been successfully saved.
Default POC voltage90% of Pmax0Normal SCRNormal X/RWECCsolar_Qstep2_HPX_SFRPT.xlsx

Voltage control - Vref changes​

The purpose of these tests is to confirm your generating system's voltage control capability. The table below outlines the sample test procedure, as well as the operating conditions under which the pre-test simulation is conducted.

DescriptionProcedurePre-test simulation initial conditionsData file name
VpocPpocQpocSCRX/R
Vref step of +3% and then -3% (±0.03 pu)
  1. Ensure the following conditions before performing the test:
    • The generating system's output is above 90% of its maximum active power capacity.
    • The generating system is in voltage control mode.
    • The generating system transformer is under auto control.
    • The generating units are under park dispatch control.
    • The voltage reference setpoint (Vref) is set such that the reactive power at the generating system's regulating point is 0 MVAr (i.e. Qpoc = 0).
  2. Confirm measurement systems are ready.
  3. Allow at least 10 seconds of recording time before applying a step.
  4. Apply a +3% step to the voltage reference setpoint (Vref).
  5. Wait until the response settles.
  6. Apply a -3% step to the voltage reference setpoint (Vref).
  7. Wait until the response settles.
  8. View the test data file to ensure it has been successfully saved.
Default POC voltage90% of Pmax0Normal SCRNormal X/RWECCsolar_Vstep1_HPX_SFVCT.xlsx
Vref step of -3% and then +3% (±0.03 pu)
  1. Ensure the following conditions before performing the test:
    • The generating system's output is above 90% of its maximum active power capacity.
    • The generating system is in voltage control mode.
    • The generating system transformer is under auto control.
    • The generating units are under park dispatch control.
    • The voltage reference setpoint (Vref) is set such that the reactive power at the generating system's regulating point is 0 MVAr (i.e. Qpoc = 0).
  2. Confirm measurement systems are ready.
  3. Allow at least 10 seconds of recording time before applying a step.
  4. Apply a -3% step to the voltage reference setpoint (Vref).
  5. Wait until the response settles.
  6. Apply a +3% step to the voltage reference setpoint (Vref).
  7. Wait until the response settles.
  8. View the test data file to ensure it has been successfully saved.
Default POC voltage90% of Pmax0Normal SCRNormal X/RWECCsolar_Vstep2_HPX_SFVCT.xlsx

Power factor control - PFref changes​

The purpose of these tests is to confirm your generating system's power factor control capability. The table below outlines the sample test procedure, as well as the operating conditions under which the pre-test simulation is conducted.

DescriptionProcedurePre-test simulation initial conditionsData file name
VpocPpocQpocSCRX/R
PFref step to 0.99 capacitive, then back to 1.0
  1. Ensure the following conditions before performing the test:
    • The generating system's output is above 90% of its maximum active power capacity.
    • The generating system is in power factor control mode and the power factor reference setpoint (PFref) is set to 1.0.
    • The generating system transformer is under auto control.
    • The generating units are under park dispatch control.
  2. Confirm measurement systems are ready.
  3. Allow at least 10 seconds of recording time before applying a step.
  4. Set the power factor reference setpoint (PFref) to 0.99 capacitive.
  5. Wait until the response settles.
  6. Set the power factor reference setpoint (PFref) to 1.0.
  7. Wait until the response settles.
  8. View the test data file to ensure it has been successfully saved.
Default POC voltage90% of Pmax0Normal SCRNormal X/RWECCsolar_PFstep1_HPX_SFPFT.xlsx
PFref step to 0.99 inductive, then back to 1.0
  1. Ensure the following conditions before performing the test:
    • The generating system's output is above 90% of its maximum active power capacity.
    • The generating system is in power factor control mode and the power factor reference setpoint (PFref) is set to 1.0.
    • The generating system transformer is under auto control.
    • The generating units are under park dispatch control.
  2. Confirm measurement systems are ready.
  3. Allow at least 10 seconds of recording time before applying a step.
  4. Set the power factor reference setpoint (PFref) to 0.99 inductive.
  5. Wait until the response settles.
  6. Set the power factor reference setpoint (PFref) to 1.0.
  7. Wait until the response settles.
  8. View the test data file to ensure it has been successfully saved.
Default POC voltage90% of Pmax0Normal SCRNormal X/RWECCsolar_PFstep2_HPX_SFPFT.xlsx

NOTE

The power factor reference step of 0.99 capacitive/inductive has been chosen arbitrarily and does relate to the reactive power reference step tests.

Transformer tap position change​

The purpose of these tests is to confirm the operation of your generating system transformer's tap changer. The table below outlines the sample test procedure, as well as the operating conditions under which the pre-test simulation is conducted.

DescriptionProcedurePre-test simulation initial conditionsData file name
VpocPpocQpocSCRX/R
Tap position up one step
  1. Ensure the following conditions before performing the test:
    • The generating system's output is above 90% of its maximum active power capacity.
    • The generating system is in its default reactive power control mode (e.g. voltage control mode).
    • The generating system transformer is under manual control (fixed tap).
    • The generating units are under park dispatch control.
  2. Confirm measurement systems are ready.
  3. Allow at least 10 seconds of recording time before applying a step.
  4. Set the transformer tap position up one step.
  5. Wait until the response settles. Ensure the voltages in the generating system are within 0.9 pu and 1.1 pu all the time.
  6. View the test data file to ensure it has been successfully saved.
Default POC voltage90% of Pmax0Normal SCRNormal X/RWECCsolar_TXstep1GEN_HPX_SFTXT.xlsx
WECCsolar_TXstep1POC_HPX_SFTXT.xlsx
Tap position down one step
  1. Ensure the following conditions before performing the test:
    • The generating system's output is above 90% of its maximum active power capacity.
    • The generating system is in its default reactive power control mode (e.g. voltage control mode).
    • The generating system transformer is under manual control (fixed tap).
    • The generating units are under park dispatch control.
  2. Confirm measurement systems are ready.
  3. Allow at least 10 seconds of recording time before applying a step.
  4. Set the transformer tap position down one step.
  5. Wait until the response settles. Ensure the voltages in the generating system are within 0.9 pu and 1.1 pu all the time.
  6. View the test data file to ensure it has been successfully saved.
Default POC voltage90% of Pmax0Normal SCRNormal X/RWECCsolar_TXstep2GEN_HPX_SFTXT.xlsx
WECCsolar_TXstep2POC_HPX_SFTXT.xlsx

danger

WECC solar model does not currently support transformer tap changing in PSCAD™ and PowerFactory, hence this test is conducted in PSS®E only.

Frequency secondary injection (via playback)​

The purpose of these tests is to confirm your generating system's operation during frequency disturbances. This test is typically completed using secondary injection testing of a test frequency signal. The table below outlines the sample test procedure, as well as the operating conditions under which the pre-test simulation is conducted.

DescriptionProcedurePre-test simulation initial conditionsData file name
VpocPpocQpocSCRX/R
Frequency ramp up to 50.1 Hz, then down to 50 Hz
  1. Ensure the following conditions before performing the test:
    • The generating system's output is above 90% of its maximum active power capacity.
    • The generating system is in its default reactive power control mode (e.g. voltage control mode).
    • The generating system transformer is under auto control.
    • The generating units are under park dispatch control and configured to frequency control mode.
  2. Confirm measurement systems are ready.
  3. Set the default deadband and droop settings.
  4. Allow at least 10 seconds of recording time before applying a step.
  5. Inject a frequency ramp signal of +0.1 Hz into the frequency controller summing junction.
  6. Wait until the response settles.
  7. Inject a frequency ramp signal of -0.1 Hz into the frequency controller summing junction to return the frequency to pre-test conditions.
  8. Wait until the response settles.
  9. View the test data file to ensure it has been successfully saved.
Default POC voltage90% of Pmax0Normal SCRNormal X/RWECCsolar_FreqPLBstep1_HPX_SFFCT.xlsx
Frequency ramp down to 49.9 Hz, then up to 50 Hz
  1. Ensure the following conditions before performing the test:
    • The generating system's output is curtailed to 50% of its maximum active power capacity.
    • The generating system is in its default reactive power control mode (e.g. voltage control mode).
    • The generating system transformer is under auto control.
    • The generating units are under park dispatch control and configured to frequency control mode.
  2. Confirm measurement systems are ready.
  3. Set the default deadband and droop settings.
  4. Allow at least 10 seconds of recording time before applying a step.
  5. Inject a frequency ramp signal of -0.1 Hz into the frequency controller summing junction.
  6. Wait until the response settles.
  7. Inject a frequency ramp signal of +0.1 Hz into the frequency controller summing junction to return the frequency to pre-test conditions.
  8. Wait until the response settles.
  9. View the test data file to ensure it has been successfully saved.
Default POC voltage50% of Pmax0Normal SCRNormal X/RWECCsolar_FreqPLBstep2_HPX_SFFCT.xlsx

Plant capacitor switching event​

The purpose of these tests is to confirm your generating system's operation during a capacitor switching event. The table below outlines the sample test procedure, as well as the operating conditions under which the pre-test simulation is conducted.

DescriptionProcedurePre-test simulation initial conditionsData file name
VpocPpocQpocSCRX/R
Switch plant capacitor in and out
  1. Ensure the following conditions before performing the test:
    • The generating system's output is above 90% of its maximum active power capacity.
    • The generating system is in its default reactive power control mode (e.g. voltage control mode).
    • The generating system transformer is under auto control.
    • The generating units are under park dispatch control.
    • The capacitor is switched out.
  2. Confirm measurement systems are ready.
  3. Allow at least 10 seconds of recording time before applying a step.
  4. Switch the plant capacitor in.
  5. Wait until the response settles.
  6. Switch the plant capacitor out.
  7. Wait until the response settles.
  8. View the test data file to ensure it has been successfully saved.
Default POC voltage90% of Pmax0Normal SCRNormal X/RWECCsolar_PlantCapSwitchGEN_HPX_SFCAP
WECCsolar_PlantCapSwitchPOC_HPX_SFCAP.xlsx

danger

WECC solar model does not currently have a capacitor modelled in PSCAD™ and PowerFactory, hence this test is conducted in PSS®E only.

Network capacitor switching event​

The purpose of these tests is to confirm your generating system's operation during a network capacitor switching event. This test is typically completed in coordination with a utility where they will switch a capacitor bank (or similar) at a nearby substation. The table below outlines the sample test procedure, as well as the operating conditions under which the pre-test simulation is conducted.

DescriptionProcedurePre-test simulation initial conditionsData file name
VpocPpocQpocSCRX/R
Switch network capacitor in
  1. Ensure the following conditions before performing the test:
    • The generating system's output is above 90% of its maximum active power capacity.
    • The generating system is in its default reactive power control mode (e.g. voltage control mode).
    • The generating system transformer is under auto control.
    • The generating units are under park dispatch control.
    • The network capacitor is switched out.
  2. Confirm measurement systems are ready.
  3. Allow at least 10 seconds of recording time before applying a step.
  4. Switch the network capacitor in.
  5. Wait until the response settles.
  6. Switch the network capacitor out.
  7. Wait until the response settles.
  8. View the test data file to ensure it has been successfully saved.
Default POC voltage90% of Pmax0Infinite SCRN/AWECCsolar_NetworkCapSwitch_HPX_SFCST.xlsx
Switch network capacitor out Default POC voltage90% of Pmax0Infinite SCRN/A

NOTE

In simulation, this test is performed by applying an overvoltage disturbance to replicate the effects of a network capacitor switching in.

tip

When using Overlay builder for the plant and network capacitor switching tests in this template, one data file was used for multiple overlay tests (i.e. switch capacitor in, and switch capacitor out). You can do this for any type of test by creating multiple tests within Overlay builder, loading the same file twice, then analyzing a different section of data.

NOTE

The tests below do not have pre-test simulations or a sample test procedure as they are typically not part of any pre-defined commissioning tests. This is because utilities typically don’t want to purposefully create network events which could increase system security risk or damage equipment. However, if such events occur on the network and recording is triggered as part of generator operations monitoring, then it is common to complete an overlay.

Two examples have been provided which outline a single network event (e.g. a network fault). However, it is more realistic that network events will include a combination of events. For example, a network fault is followed by a network switching event because a line has been disconnected to clear the fault. In these instances, you may need to simulate multiple events in the model to complete the overlay.

Network fault event (via playback)​

The purpose of this test is to confirm your generating system's operation during voltage disturbances (e.g. a nearby network fault). The table below outlines the operating conditions to be used for performing the simulations.

DescriptionVpocPpocQpocSCRX/RData file name
Network fault of 0.62 pu residual for a duration of 220 msAs per real-world dataAs per real-world dataAs per real-world dataInfinite SCRN/AWECCsolar_Network_FaultEvent.xlsx
tip

To set the voltage at the connection point, the simulation is conducted at infinite SCR which allows the Thévenin equivalent voltage source to 'force' the connection point voltage to the desired value from the real-world data.

NOTE

We have assumed that the voltage disturbance is applied in the model by using a Thévenin equivalent voltage source playback of the real-world data connection point voltage. However, for very deep faults (e.g. 10% Vpoc residual voltage) we don’t recommend using this playback methodology since it has been known to cause unrealistic and undesirable generating systems responses in the model. If your network event is a very deep fault, we recommend using the VDISTURBANCE Command instead.

Network switching event (via SCR change)​

The purpose of this test is to confirm your generating system's operation during network switching events (e.g. a line outage). The table below outlines the operating conditions to be used for performing the simulations.

DescriptionVpocPpocQpocSCRX/RData file name
Network switching event causing SCR and X/R to change from maximum (normal) to minimumAs per real-world dataAs per real-world dataAs per real-world dataAs per real-world dataAs per real-world dataWECCsolar_Network_SwitchingEvent.xlsx

Sources​

Revision history​

Version 1 | 30 September 2025​

  • First release.