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Example: How to overlay results with real-world data

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Example version: v3

Software required:

PSS®E
PowerFactory
Preview of example's gridmo Flow showing Nodes

Background​

To draw meaningful conclusions from power system modelling, models must accurately represent actual plant performance. Additionally, performing simulations is not enough to validate plant performance and therefore commissioning/Hardware-in-the-Loop (HIL) testing is performed to validate actual plant performance. Based on both of these requirements, it is often useful to overlay the results from commissioning/HIL testing and model simulations to ensure the following:

  • Model accuracy
  • Real-world plant performance

The Data Node and Overlay builder Node are used to help with such activities and this example demonstrates how to use these two Nodes. The example is divided into 6 parts which step you through the process in increasing complexity.

The tutorial below provides a step by step approach to putting together the example yourself starting from a new project. You can view the final result of this tutorial by opening the example in the web application.

note

This multi-part example assumes you have a basic understanding of the gridmo platform. If you are new to gridmo, please see the Getting started guide.

Tutorial​

Part 1: Plotting data​

In this first part, we will show you how to import real-world data into the gridmo platform.

1.1: Ensure you have the data you want to import in your Engine's Inputs folder​

For this example, we will be using the sample data files provided with the gridmo Engine. Ensure you have the following data files in the gridmo\data folder within your Inputs folder:

  • e002_q_step1_data.csv
  • e002_q_step2_data.csv

1.2: Setup gridmo project for importing data​

Create a new gridmo Project and add the following Nodes:

  • Start Node
  • Data Node
  • Plot Node
  • End Node

And connect the Nodes together as shown below.

example of a data connected to a plot

1.3: Configure the Data Node​

  • Double click on the Data Node to open the configuration window.
  • Set the Input file name field to the relative path of the .csv file you want to import, such as gridmo\data\e002_q_step1_data.csv.
  • Switch to the Define outputs tab.
  • Add the following OUTPUT commands to convert the columns in the .csv file to Internode Variables for use in gridmo.
Data Node's Outputs field
// Convert from CSV column names into Internode Variables
OUTPUT, COL=V_pu, NAME=i_ch_poc_v
OUTPUT, COL=P_MW, NAME=i_ch_poc_p
OUTPUT, COL=Q_MVAr, NAME=i_ch_poc_q

The above commands convert each column from the name in the .csv file to an Internode Variable for use in gridmo. Specifically:

  • The column V_pu can be accessed by Nodes connected to this Data Node using i_ch_poc_v.
  • The column P_MW can be accessed by Nodes connected to this Data Node using i_ch_poc_p.
  • The column Q_MVAr can be accessed by Nodes connected to this Data Node using i_ch_poc_q.
tip

If your .csv file is using a different unit than the unit you want for your simulation, you can use the optional argument VALSCALE= to apply a multiplicative scale.

You do not need to directly modify the source .csv file.

For example, if you .csv data file has voltage in kV (with a 33 kV base) you can use the following command:

Example of using VALSCALE= to convert kV to per unit
OUTPUT, COL=V_at_33kV, NAME=i_ch_poc_v, VALSCALE=1/33

1.4: Configure the Plot Node​

  • Double click on the Plot Node to open the configuration window.
  • Enter an output file name, such as Overlaying Data\Part 1 - Plotting data.
  • Select Document (.pdf) and Interactive visualisation (.html) to output PDF and HTML files.
  • Enter a plot title, such as E002 - Overlaying results with real-world data.
  • Enter a plot subtitle, such as Part 1: Plotting data.
  • In the Define Subplots tab:
    • Set the x-axis Min to 0 and x-axis Max to 20.
    • Under Subplots select 1 page, 2 rows and 2 columns.
    • Click on the + to add a new subplot for Vpoc, Ppoc and Qpoc. For each subplot:
      • Enter a title in Subplot title, such as Vpoc.
      • Under y-axis Channels enter each of the Internode Variables with the double curly brackets, such as {{i_ch_poc_v}}
example screenshot of configured subplots in Plot Node

1.5: Launch the simulation and review the results​

  • Launch the simulation.
  • The output plot should show the real-world data you imported plotted as per your configuration of the Plot Node.
  • We can see in our outputs folder (example below) that we have plotted the real-world data:
    • ✅ Point of connection voltage, active power and reactive power are all plotted.
    • ✅ We can see in our data that the test being recorded appears to be a single reactive power step from 10 MVAr to about 26 MVAr.
example of results from step 1, showing data only, POC P Q and V

Part 2: Overlaying simulations​

Now that we have imported real-world data, we will overlay this with the results of a dynamic study in PSS®E or PowerFactory. This is a common task when benchmarking dynamic simulations against real-world data.

2.1: Add PSS®E / Powerfactory Nodes to your existing Run​

  • PSS®E Static Node (or PowerFactory Static Node).
  • PSS®E Dynamic Node (or PowerFactory Dynamic Node).

2.2: Connect the Nodes​

  • The PSS®E Static Node should be connected to the PSS®E Dynamic Node (or PowerFactory Static Node to the PowerFactory Dynamic Node).
  • The existing Data Node should be connected from the Start Node to the Plot Node.
  • The PSS®E Dynamic Node (or PowerFactory Dynamic Node) should also be connected to the Plot Node.
example of a data Node in parallel with a psse static and dynamic Node, both being plotted

2.3: Configure the PSS®E Static / PowerFactory Static Node​

PSS®E​
  • In the Select model tab, set the Model to gridmo\wecc-solar\psse\solar.sav to use an example 175 MW solar farm's PSS®E case file.
  • In the Define simulation & Define outputs tab, add the commands below to the Commands field, which describe what we want the PSS®E model to initialize to:
PSS®E Static Node's Commands field
// Begin PSSE static simulation

// Set the Thevenin equivalent source impedance such that SCR is 7.5 and X/R is 4
SET, LINE=1000->999#1, STATUS=IN, SCR=7.5, XR=4

// Configure Vpoc as 1.0
// NOTE: The Thevenin equivalent voltage source (i.e. swing bus) is controlled to achieve the desired Vpoc target.
CONTROL, GEN=999#1, Q=VDIRECT, ATBUS=1000, QMIN=-9999, QMAX=9999, VTARGET=1.00

// Configure Ppoc and Qpoc of our solar farm such that Ppoc = 175 MW and Qpoc = 0 MVAr
CONTROL, GEN=91003#S1, ATLINE=1001->1000#1, P=175
CONTROL, GEN=91003#S1, ATLINE=1001->1000#1, Q=FIXED, QTARGET=0

// Solve the case
//NOTE: The SOLVE Command slowly resolves all CONTROL commands at the same time.
SOLVE
PowerFactory​
  • In the Select model tab, set the Model to gridmo\wecc-solar\dpf\wecc-solar.pfd to use an example 175 MW solar farm's PSS®E case file.
  • In the Define simulation & Define outputs tab, add the commands below to the Commands field, which describe what we want the PowerFactory model to initialize to:
PowerFactory Static Node's Commands field
// Begin PowerFactory static simulation

// Set the Thevenin equivalent source impedance such that SCR is 7.5 and X/R is 4
SET, LINE=POC->THEV#Zth, STATUS=IN, SCR=7.5, XR=4

// Configure Vpoc as 1.0
// NOTE: The Thevenin equivalent voltage source is controlled to achieve the desired Vpoc target.
SET, OBJECT_NAME=Load Flow Controller - Vpoc, VARIABLE=usetp, VAL=1.00

// Configure Ppoc and Qpoc of our solar farm such that Ppoc = 175 MW and Qpoc = 0 MVAr
SET, OBJECT_NAME=Power-Frequency Controller, VARIABLE=psetp, VAL=175
SET, OBJECT_NAME=Station Control, VARIABLE=qsetp, VALSCALE=-1, VAL=0

// Solve the case
SOLVE

The above commands:

  • Set the SCR and X/R ratio for this example SMIB model to 7.5 and 4 respectively.
  • Control the example solar farm to achieve P=175 MW, Q=0 MVAr at the solar farm's connection point.
  • Use the infinite bus generator to achieve 1.00 pu voltage at the connection point.

2.4: Configure the PSS®E Dynamic / PowerFactory Dynamic Node​

PSS®E​
  • Select the tickbox to enable Use model from linked PSS®E Static Node.
  • Set the Dynamics model data to gridmo\wecc-solar\psse\solar.dyr to use an example 175 MW solar farm's PSS®E dynamic data record.
  • In the Define simulation tab:
    • Set the Simulation time [seconds] to 20 seconds.
    • Add the following commands into the Actions field:
PSS®E Dynamic Node's Actions field
// Put solar farm in Q control mode
CONTROL, AT=0, ICON=M+5, GEN=91003#S1, DYRMODEL=REPCA1, VAL=0

// Complete a Qref step at 5 seconds
// NOTE: REPCA1 model definition, VAR (L+1) = Reactive power reference (Qref).
// NOTE: VALSCALE=1/200 for the Qref Command since values are specified on MBASE (200 MVA).
CONTROL, GEN=91003#S1, DYRMODEL=REPCA1, VAR=L+1, VALSCALE=1/200, AT=5, VAL=26.25
  • In the Define outputs tab, add the following outputs:
PSS®E Dynamic Node's Outputs field
OUTPUT, BUS=1000, VAL=V, NAME=i_ch_poc_v
OUTPUT, LINE=1001->1000#1, VAL=P, NAME=i_ch_poc_p
OUTPUT, LINE=1001->1000#1, VAL=Q, NAME=i_ch_poc_q
PowerFactory​
  • Select the tickbox to enable Use model from linked PowerFactory Static Node.
  • Set the Dynamics user models to gridmo\wecc-solar\ to use an example 175 MW solar farm's PowerFactory dynamic models.
  • In the Define simulation tab:
    • Set the Simulation time [seconds] to 20 seconds.
    • Add the following commands into the Actions field:
PowerFactory Dynamic Node's Actions field
// Put solar farm in Q control mode
CONTROL, OBJECT_NAME=REPC_A Plant Control, VARIABLE=RefFlag, AT=-1, VAL=0

// Complete a Qref step at 5 seconds
// NOTE: REPC_A Plant Control model definition, Qrefp = Reactive power reference (Qref).
// NOTE: VALSCALE=1/200 for the Qref Command since values are specified on MBASE (200 MVA).
CONTROL, OBJECT_NAME=REPC_A Plant Control, VARIABLE=Qrefp, VALSCALE=1/200, AT=5, VAL=26.25
  • In the Define outputs tab, add the following outputs:
PowerFactory Dynamic Node's Outputs field
OUTPUT, BUS=POC, VAL=V, NAME=i_ch_poc_v
OUTPUT, LINE=POC->THEV#Zth, VAL=P, NAME=i_ch_poc_p
OUTPUT, LINE=POC->THEV#Zth, VAL=Q, NAME=i_ch_poc_q
  • The above commands:
    • Set the solar farm's controller into fixed reactive power reference mode.
    • Set the initial active power to 175 MW and sets the initial reactive power to 0 MVAr.
    • Perform a single reactive power reference step at 5 seconds from 0 MVAr to 26.25 MVAr.
    • Measure the voltage magnitude at the connection point and assign the name i_ch_poc_v.
    • Measure the active power at the connection point and assign the name i_ch_poc_p.
    • Measure the reactive power at the connection point and assign the name i_ch_poc_q.
tip

As we are naming the outputs i_ch_poc_v, i_ch_poc_p and i_ch_poc_q - which are the same as the names we defined as the outputs of the Data Node - we do not need to make any changes to the Plot Node.

The Plot Node will automatically plot all connected Nodes with the same output names on the same subplot, benchmarking the imported data, PSS®E Dynamic simulation and PowerFactory Dynamic simulation results.

2.5: Launch the simulation and review results​

  • Launch the simulation.
  • We can see in our outputs folder (example below) that we have plotted the real-world data against the dynamic simulation results:
    • ✅ There is a reactive power step in the PSS®E, PowerFactory and the real-world data
    • ⚠️ The benchmarking is really poor. The reactive power steps are done at different times during the simulation and the initial active power isn't 175 MW, the initial reactive power isn't 0 MVAr and the POC voltage magnitude isn't 1.00 pu.
example of results from step 2, showing psse dynamic and data overlayed but with a very poor benchmark

Part 3: Shift data in x-axis​

In this part, we will use the Data Node's alignment capability to improve the benchmark with the PSS®E result.

In the previous section, we overlayed the dynamic simulation results with our real-world data and saw a very poor benchmark, as the time of the reactive power step in the data was different to the time in simulation. This is because it is very hard to have an event happen in real life at a specific time after starting to record data (e.g. exactly 5 seconds after starting meter recording). To improve this, we need to review our real-world data, find the index at which the event occurs and shift the data accordingly.

3.1: Open the source data in Excel to find the index of the step​

You can find the example data in your gridmo Engine's Inputs folder in the gridmo folder at ...\gridmo\data\. The file we are using for this example is e002_q_step1_data.csv.

We can see:

  • The time column starts from approximately 377 seconds, an arbitrary number. Having arbitrary date/time values is relatively common for real-world data which use a timestamp or similar (e.g. data doesn't always start at 0 seconds).
  • By creating a 2-D line plot using the Q_MVAr column, we can see that the reactive power step occurs at an index (row number in Excel) of approximately 7810.
  • Our aim is to tell the gridmo platform to shift the real-world data so that the reactive power step occurs at a defined time in the 'simulation' world e.g. at same time as the PSS®E or PowerFactory simulation.
example of excel showing the row index
info

gridmo uses row indices (numbers) instead of time values for alignment.

This is because:

  • The data might be in a complex timestamp format, which is common if exported from an Elspec PQM (for example 17/04/2024 7:15:32 PM). This adds unnecessary calculation burden to convert a timestamp into seconds since start of a simulation.
  • Even if the data is in a simple format like seconds (similar to our example data), requiring a time offset requires extra calculations on your behalf if the data doesn't start at 0 seconds. This is especially common if exported from real-world data.

3.2: Configure the Data Node to use manual alignment mode​

  • In your existing Run, double click on the Data Node.
  • Select the Process data tab in the Node configuration window.
  • Select Manual align button in the X-axis shift area.
    • In the Row number field enter the row we found from excel, in our example 7810.
    • In the Time [seconds] field enter the time in seconds that the step occurs in the simulation, in our example 5 seconds.
  • Click Apply to save the changes.

We have now configured the Data Node to shift the real-world data so that the reactive power step occurs at 5 seconds in the simulation world.

3.3: Configure the PSS®E Dynamic / PowerFactory Dynamic Node and Plot Node to have a shorter simulation time​

Now that we've shifted the real-world data, we can update the PSS®E Dynamic, PowerFactory Dynamic and Plot Nodes to have a shorter simulation time.

  • Double click on the PSS®E Dynamic / PowerFactory Dynamic Node.
  • Under the Define simulation tab, set the Simulation time [seconds] to 10 seconds.
  • Click Apply to save the changes.
  • Double click on the Plot Node.
  • Under the Define subplots tab, set the x-axis Min [seconds] to 4 and the x-axis Max [seconds] to 10.
  • Click Apply to save the changes.

3.4: Launch the simulation and review results​

  • Launch the simulation.
  • We can see in our outputs folder (example below) that our real-world data has been shifted:
    • ✅ The reactive power step now occurs at 5 seconds in the simulation.
    • ⚠️ The benchmarking is better, but still poor (initial active power, reactive power and voltage are still incorrect) .
example of results from step 3, showing psse dynamic and data overlayed, benchmark still poor but now happens at the same time

Part 4: Initialize simulations from data​

In this part, we will initialize the dynamic simulations from the initial values of the imported data. We're going to modify our Flow so that we can export values from the Data Node into PSS®E Static / PowerFactory Static Node. This will allow us to use the initial values from the real-world data.

4.1: Modify your Run such that the PSS®E Static / PowerFactory Static Node is linked to the Data Node​

Update your gridmo Run by dragging Nodes (left click and drag) and deleting edges (left click, then press the Delete key) so that the PSS®E Static / PowerFactory Static Node depends on the Data Node as shown below.

example of updated Flow chart with data first
note

In our re-arranged Run, the Data Node is still connected to the Plot Node and we do not require any changes to the Plot Node for this step.

4.2: Configure the Data Node to export the initial values​

  • Double click on the Data Node.
  • Select the Define outputs tab in the Node configuration window.
  • Add the following rows in addition to those which already exist in this field.
Data Node's Outputs field
// Export values at the start of the data - note the AT=0 arguments have been added
OUTPUT, COL=V_pu, NAME=i_ch_poc_v_initial, AT=0
OUTPUT, COL=P_MW, NAME=i_ch_poc_p_initial, AT=0
OUTPUT, COL=Q_MVAr, NAME=i_ch_poc_q_initial, AT=0
  • The above OUTPUT commands has the optional AT= argument, which means export the single value instead of the entire column of data. We have set them to output at 0 seconds (after being shifted by the manual alignment mode we turned on in the previous step). Specifically:
    • The Internode Variable i_ch_poc_v_initial stores the initial voltage from the Data Node (in per unit - the same unit as the in the .csv file).
    • The Internode Variable i_ch_poc_p_initial stores the initial active power from the Data Node (in MW - the same unit as the in the .csv file).
    • The Internode Variable i_ch_poc_q_initial stores the initial reactive power from the Data Node (in MVAr - the same unit as the in the .csv file).
  • Click Apply to save the changes

4.3: Configure the PSS®E Static / PowerFactory Static Node to use the new Internode Variables​

Now that the Data Node is exporting the initial values, we can update the PSS®E Static / PowerFactory Static Node to use these values.

PSS®E​
  • Double click on the PSS®E Static Node.
  • Select the Define simulation & Define outputs tab in the Node configuration window.
  • Replace the commands in the Commands field with the following (the lines which have changed from the previous steps are highlighted):
PSS®E Static Node's Commands field
// Begin PSSE static simulation

// Set the Thevenin equivalent source impedance such that SCR is 7.5 and X/R is 4
SET, LINE=1000->999#1, STATUS=IN, SCR=7.5, XR=4

// Configure Vpoc, Ppoc and Qpoc using values imported from the Data Node 
// NOTE: The Thevenin equivalent voltage source (i.e. swing bus) is controlled to achieve the desired Vpoc target.
CONTROL, GEN=999#1, Q=VDIRECT, ATBUS=1000, QMIN=-9999, QMAX=9999, VTARGET={{i_ch_poc_v_initial}}
CONTROL, GEN=91003#S1, ATLINE=1001->1000#1, P={{i_ch_poc_p_initial}}
CONTROL, GEN=91003#S1, ATLINE=1001->1000#1, Q=FIXED, QTARGET={{i_ch_poc_q_initial}}

// Solve the case
//NOTE: The SOLVE Command slowly resolves all CONTROL commands at the same time.
SOLVE
PowerFactory​
  • Double click on the PowerFactory Static Node.
  • Select the Define simulation & Define outputs tab in the Node configuration window.
  • Replace the commands in the Commands field with the following (the lines which have changed from the previous steps are highlighted):
PowerFactory Static Node's Commands field
// Begin PowerFactory static simulation

// Set the Thevenin equivalent source impedance such that SCR is 7.5 and X/R is 4
SET, LINE=POC->THEV#Zth, STATUS=IN, SCR=7.5, XR=4

// Configure Vpoc, Ppoc and Qpoc using values imported from the Data Node 
// NOTE: The Thevenin equivalent voltage source is controlled to achieve the desired Vpoc target.
SET, OBJECT_NAME=Load Flow Controller - Vpoc, VARIABLE=usetp, VAL={{i_ch_poc_v_initial}}
SET, OBJECT_NAME=Power-Frequency Controller, VARIABLE=psetp, VAL={{i_ch_poc_p_initial}}
SET, OBJECT_NAME=Station Control, VARIABLE=qsetp, VALSCALE=-1, VAL={{i_ch_poc_q_initial}}

// Solve the case
SOLVE
  • The above commands:
    • Set the SCR and X/R ratio for this example SMIB model to 7.5 and 4 respectively.
    • It then controls the example solar farm to achieve an active power and reactive power from the Internode Variables i_ch_poc_p_initial and i_ch_poc_q_initial we defined in the Data Node above.
    • It also uses the infinite bus generator to achieve a voltage at the connection point as per the i_ch_poc_v_initial Internode Variable.
  • Click Apply to save the changes

4.4: Launch the simulation and review results​

  • Launch the simulation.
  • We can see in our outputs folder (example below) that our real-world data has been shifted:
    • ✅ The reactive power step occurs at 5 seconds in the simulation.
    • ✅ The initial values of the POC voltage, active power and reactive power now match between the real-world data and the dynamic simulation.
improved benchmark

Part 5: Multiple tests with loops​

In this part, we will use a Loop: Start Node to set up multiple tests. This is useful for creating overlays for different tests (such as different Qref steps), importing different data files or varying other test variables such as simulation length.

For this example, we will be adding an additional test to our existing Run, with a reactive power step down to -26.25 MVAr at 5 seconds, using a different data file.

5.1: Add Loop: Start and Loop: End Nodes and modify your Run​

Add the following Nodes to your project:

  • Loop: Start Node
  • Loop: End Node

Re-arrange your Run to wrap the existing Nodes within the Loop: Start and Loop: End Nodes and connect them as shown below:

overlay loop

5.2: Configure the Loop: Start Node​

  • Double click on the Loop: Start Node.
  • Delete the 3rd row (which was added by default) so that there are two rows (Loops) and add new Loop Variables such that there are 8 Loop Variables in total.
  • Rename each Loop Variable (at the top of the column) as follows:
    • l_test_name
    • l_time_step
    • l_filename
    • l_simulation_time
    • l_psse_ds_commands
    • l_powerfactory_ds_commands
    • l_manual_align_time
    • l_manual_align_index
  • Fill in the fields of each Loop Variables with the following:
    • l_test_name: Enter Qref step up for Loop 1 and Qref step down for Loop 2.
    • l_time_step: Enter 0.001 for both Loops.
    • l_filename: Enter e002_q_step1_data.csv for Loop 1 and e002_q_step2_data.csv for Loop 2.
    • l_simulation_time: Enter 15 for both Loop 1 and Loop 2.
    • l_manual_align_time: Enter 5 for both Loops.
    • l_manual_align_index: Enter 7810 for Loop 1 and 16020 for Loop 2.
  • For l_psse_ds_commands and l_powerfactory_ds_commands, enter the following commands for Loop 1:
l_psse_ds_commands fields for Loop 1:
CONTROL, GEN=91003#S1, DYRMODEL=REPCA1, ICON=M+5, AT=-1, VAL=0
CONTROL, GEN=91003#S1, DYRMODEL=REPCA1, VAR=L+1, VALSCALE=0.875, AT=5, VAL=0.15
l_powerfactory_ds_commands fields for Loop 1:
CONTROL, OBJECT_NAME=REPC_A Plant Control, VARIABLE=RefFlag, AT=-1, VAL=0
CONTROL, OBJECT_NAME=REPC_A Plant Control, VARIABLE=Qrefp, VALSCALE=0.875, AT=5, VAL=0.15
  • For Loop 2, enter the following for the l_psse_ds_commands and l_powerfactory_ds_commands fields:
l_psse_ds_commands fields for Loop 2:
CONTROL, GEN=91003#S1, DYRMODEL=REPCA1, ICON=M+5, AT=-1, VAL=0
CONTROL, GEN=91003#S1, DYRMODEL=REPCA1, VAR=L+1, VALSCALE=0.875, AT=5, VAL=-0.15
l_powerfactory_ds_commands fields for Loop 2:
CONTROL, OBJECT_NAME=REPC_A Plant Control, VARIABLE=RefFlag, AT=-1, VAL=0
CONTROL, OBJECT_NAME=REPC_A Plant Control, VARIABLE=Qrefp, VALSCALE=0.875, AT=5, VAL=-0.15

Your Loop: Start Node should now be configured as follows:

loopstart

5.3: Configure the existing Nodes to use Loop Variables​

We will now use these new Loop Variables within the existing Nodes in our Run.

Data Node​
  • Double click on the Data Node.
  • In the Input file name field, replace gridmo\data\e002_q_step1_data.csv with gridmo\data\$l_file_name.
  • Switch to the Process data tab.
  • In the Row number field, replace 7810 with $l_manual_align_index.
  • In the Time [seconds] field, replace 5 with $l_manual_align_time.
PSS®E Dynamic / PowerFactory Dynamic Node​
  • Double click on the PSS®E Dynamic / PowerFactory Dynamic Node.
  • For PSS®E Dynamic Node:
    • Switch to the Define simulation tab.
    • In the Simulation time [seconds] field, enter the Loop Variable $l_simulation_time.
    • In the Actions field, replace the existing CONTROL commands with $l_psse_ds_commands.
  • For PowerFactory Dynamic Node:
    • Switch to the Define simulation tab.
    • In the Simulation time [seconds] field, enter the Loop Variable $l_simulation_time.
    • In the Actions field, replace the existing CONTROL commands with $l_powerfactory_ds_commands.
Plot Node​
  • Double click on the Plot Node.
  • Switch to the Define subplots tab and replace the x-axis: Max field with $l_simulation_time.

5.4: Launch simulation and review results​

  • Launch the simulation.
  • We can see in our outputs folder that we have two plots for the two scenarios in our Loops.
    • ✅ Loop 1 shows the reactive power step up at 5 seconds to approximately 26 MVAr.
    • ✅ Loop 2 shows the reactive power step down at 5 seconds to approximately -26 MVAr.
loop1loop2
tip

By using the Loop: Start Node, you can now setup multiple overlays in one place by modifying the Loop Variables for input data files, type of tests, simulation times, manual alignment indexes and the associated PSS®E and PowerFactory commands.

Part 6: Overlay builder​

In this final part, we will add Overlay builder which makes it easy to configure the Loop: Start and Data Nodes in the previous example.

6.1: Add Overlay builder and modify Run​

  • Delete the Loop: Start and Data Nodes in your existing Run.
  • Click on the '+' icon on the left-hand side and select Overlay builder under Node Builders, and connect it between the Start Node and PSS®E Dynamic / PowerFactory Dynamic Nodes as follows:
overlaybuilder

6.2: Configure Overlay builder​

Setup​
  • Double click on the Overlay builder to open the Overlay builder window.
  • Tick PSS®E and PowerFactory checkboxes under Overlay data with the following software.
  • Set the Input folder field to gridmo\data directory which contains the example 175 MW solar farm's data, and click Next.
Add tests and input data​
  • In the top-left corner, click + Add another test and rename the test using the pencil icon to Qref step up.
  • Below Add tests, click the Select file(s) button and navigate to the gridmo\data directory and select the e002_q_step1_data.csv data file.
  • In the Input time step [s] field, enter 0.001. The Define output channels for all tests section should now appear.
Define outputs​
  • In Define output channels for all tests, click Add output and then the dropdown under Column. You should see here the column headings from the example .csv data file. Select P_MW.
  • Now in the Output name field, enter i_ch_poc_p which is the Internode Variable name for active power.
  • In the Type field dropdown, select PQS.
  • Repeat the above for:
    • Q_MVAr with output name i_ch_poc_q and select PQS for the Type.
    • V_pu with output name i_ch_poc_v and select V for the Type.
  • We will now extract the initial values of the data for initialising our dynamic simulations. Click Add advanced outputand select P_MW again.
  • In the Start field, enter 0 (which means we will extract the active power value at T=0 seconds).
  • In the Advanced output name field, enter i_ch_poc_p_initial which is the Internode Variable for the initial value of active power.
  • Repeat the above for:
    • Q_MVAr with output name i_ch_poc_q_initial.
    • V_pu with output name i_ch_poc_v_initial.
Define events​

We will now tell Overlay builder when the Qref step occurs and what commands to use for the dynamic simulations.

  • In Define events, click the dropdown under Data to display and select i_ch_poc_q or Q_MVAr and set the Simulation time [s] field to 10. You will now see the reactive power data in graph.
  • To tell Overlay builder when the Qref step occurs, you can do the following:
    • Click on the point at which the Qref step occurs directly, by selecting a point on the graph.
    • Alternatively, click Auto-generate events which will automatically find the time at which Qref step occurs.
  • Note that you can also adjust the point using the - + buttons below the plot in the Event 1 box.

Now that we have recorded the time at which the Qref step occurs, we need to tell Overlay builder the final value of Q_MVAr. From the graph, we can see this value is around 26.25 MVAr. However, our model receives the reactive power reference command in per unit on a base of 175 MW (the plant's rated capacity). Hence, our Qref command will be 26.25/175 = 0.15 pu.

  • In the Event 1 box in the VAL= field, enter 0.15.

We will now configure the second test which has a reactive power reference step down to -26.25 MVAr.

  • Add the second test by clicking + Add another test and name it Qref step down.
  • Click Select file(s) and add the same .csv data file as the first test gridmo\data\e002_q_step2_data.csv.
  • Set the Input time step [s] field to 0.001.
  • Note that all the output channels configured for the first test are already pre-populated for the second test.
  • In Define events, select i_ch_poc_q under Data to display and repeat the same steps as the first test but this time defining an event with AT=5 and VAL=-0.15.
Review generated values​

In the Review generated values section on the right-hand side, you will now see the generated Loop Variables used for the dynamic simulation.

note

Overlay builder will automatically generate commands to configure the PSS®E command Loop Variable l_psse_ds_commands and PowerFactory command Loop Variable l_powerfactory_ds_commands using your project's Global Variables.

Your Overlay builder window should now look as below:

overlaybuildersetup
Generate Nodes​
  • Finish the Overlay builder setup by clicking Generate Nodes on the bottom-right corner.
  • You will now be able to view the configured Loop: Start and Data Nodes within the Overlay builder box. Notice here that these Nodes are identical to the Loop: Start and Data Nodes from Step 5, which we set up manually without Overlay builder.
danger

If you open an Overlay builder Node and you are unable to find your input data, you will need to select the input files again as the Overlay builder does not save the input data files within the gridmo project file.

obdatanotfound

Alternatively, you can export the data files from the original browser where Overlay builder was created by right clicking on the Overlay builder Node and selecting Export overlay data. This will download a .json file which you can import into your current project by right clicking and selecting Import overlay data.

obdataexport

6.3: Launch simulation and review results​

  • Launch the simulation.
  • We can see in our outputs folder that our plots are identical to Step 4, this time configured with Overlay builder.
    • ✅ Loop 1 shows the reactive power step up at 5 seconds to approximately 26 MVAr.
    • ✅ Loop 2 shows the reactive power step down at 5 seconds to approximately -26 MVAr.
loop1loop2

Revision history​

Version 3 | 21 September 2025​

New
  • Added new Runs for importing from data (Part 1), initializing from data while using manual alignment (Part 4), multiple tests using loops (Part 5) and using Overlay builder (Part 6).
Improvements
  • Renamed 'No alignment' Run to 'Part 2: Overlaying simulations' and Manual alignment Run to 'Part 3: Shift data in x-axis', along with other updates required to use new data files.
  • Removed outdated PowerFactory only and PSCAD™ only Runs, as well as PSS®E only Runs which used auto alignment.

Version 2 (v1.4.15.6) | 23 July 2024​

  • Updated Sticky Node helper text in example.

Version 1 (v1.4.15) | 20 June 2024​

  • First release of example file.