Skip to main content

Example: How to initialize dynamic studies from static study results

gridmo logo

Example version: v7

Software required:

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

Background​

Example file to demonstrate how to initialize dynamic studies from static study results. By default, uses PSS®E to initialize PSCAD™ - but can be modified to use PowerFactory instead.

Why initialize from static study results?​

Generator interconnection studies are increasingly being completed using multiple power systems software packages, where the results from each package must be benchmarked. It can be difficult to ensure accurate benchmarking across different software packages. One approach to improve the alignment of the dynamic results between packages is to initialize the dynamic studies using the results from a common static study.

For example, you may have a complex generating system with multiple tap changers, switched reactive plant (harmonic filters, SVCs etc) and want to use the result of a static study completed in PSS®E or PowerFactory to initialize a dynamic study in a different software package, such as PSCAD™.

Common values exported from static study results​

The following values are commonly exported from static study results and used to initialize dynamic studies:

  • Plant statuses:
    • Tap positions of any on-load tap changers (see OUTPUT, VAL=TAPRATIO).
    • Step positions or status of any switched reactive plant (e.g. SVCs, switched caps, harmonic filters).
  • Static study results:
    • Voltage magnitude at a bus, typically the infinite or reference bus for the generating system (see OUTPUT, VAL=V).
    • Voltage angle at a bus, typically the infinite or reference bus for the generating system (see OUTPUT, VAL=ANGLE).
  • Generating system target values:
    • Power factor target on a line, typically the line connecting the generating system to the grid (see OUTPUT, VAL=PF).
    • Voltage droop target on a line/bus, typically the line connecting the generating system to the grid (see OUTPUT, VAL=VDROOPTARGET).
tip

Simple generating systems (those with simple tap changer controls and no dynamic/switched reactive plant) may not require initialization from a static simulation at all.

Specifically, if you only require infinite bus voltage to be calculated to achieve a desired point of connection (POC) voltage, you can use the following Commands to turn on smiby's automatic infinite bus voltage calculation function in the PSCAD™ Node's Commands field - removing the need for a static simulation to calculate the infinite bus voltage altogether.

Add the following to a PSCAD™ Node's Actions field to turn on auto infinite bus voltage calculation mode
SET_VTHEV, VAL_PPOC=POC_P_DESIRED_IN_MW, VAL_QPOC=POC_Q_DESIRED_IN_MVAR, VAL_VPOC=POC_V_DESIRED_IN_PU

Tutorial​

In the following tutorial, we are going to configure a PSS®E static simulation to export the voltage magnitude at the infinite bus. We will then use this value to initialize a PSCAD™ simulation of a solar farm.

note

The following example assumes you have a basic understanding of the gridmo platform. If you are new to gridmo, please see the Getting started guide.

1) Start a new gridmo Project and add the following Nodes​

  • Start Node
  • PSS®E Static Node (or PowerFactory Static Node)
  • PSCAD™ Node
  • Plot Node
  • End Node

2) Connect the Nodes as per below​

example node layout

3) Configure the PSS®E Static Node​

  • Double click on the PSS®E Static Node to open the configuration window.
  • Set the Model to gridmo\wecc-solar\psse\solar.sav to use an example 175 MW solar farm's PSS®E case file.
  • Select the Define simulation & Define outputs tab.
  • Under the Commands field, add the following Commands:
PSS®E Node's Commands field
SET, LINE=1000->999#1, STATUS=IN, SCR=7.5, XR=4

CONTROL_VDIRECT, GEN=999#1, ATBUS=1000, VAL=1.00
CONTROL_P, GEN=[DEFINITION=91003#S1], ATLINE=1001->1000#1, METERBUS=1000, VAL=175
CONTROL_Q, GEN=[DEFINITION=91003#S1], ATLINE=1001->1000#1, METERBUS=1000, VAL=0

SOLVE
OUTPUT, BUS=999, VAL=V, NAME=i_v_thev_initial
  • 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 P=175 MW, Q=0 MVAr at the solar farm's connection point.
    • It also uses the infinite bus generator to achieve 1.00 pu voltage at the connection point.
    • Finally, it outputs the voltage magnitude at the infinite bus and assigns the name i_v_thev_initial inside the gridmo simulation. This is creating an Internode Variable.

4) Configure the PSCAD™ Node​

  • Double click on the PSCAD™ Node to open the configuration window.
  • Set the Workspace to gridmo\wecc-solar\pscad\wecc_solar_wspace.pswx to use the same solar farm's PSCAD™ workspace file.
  • Select the Define simulation tab.
  • Set the Simulation time [seconds] to 10 seconds.
  • Under the Actions field add the following actions
PSCAD™ Node's Actions field
CONTROL, CH=SCR, AT=0, VAL=7.5
CONTROL, CH=XR, AT=0, VAL=4
SET, CNAME=smiby, PARAM=vinf, VAL={{i_v_thev_initial}}
CONTROL, CH=1, AT=0, VAL=1
CONTROL, CH=2, AT=0, VAL=0
CONTROL, CH=2, AT=5, VAL=0.1

The above Commands:

  • Set the SCR and X/R ratio for this example SMIB model to 7.5 and 4 respectively.
  • Set the parameter called vinf (which is the initial voltage magnitude at the infinite bus) to the value of i_v_thev_initial which comes from the PSS®E Static Node (an Internode Variable).
  • Sets channel 1 (which is connected to the solar farm's active power control) to 1.0 pu (meaning maximum power e.g. 175 MW) and channel 2 (which is connected to the solar farm's reactive power control) to 0 pu (meaning 0 MVAr). Note these values could also be exported from the static simulation using an OUTPUT, LINE=..., VAL=..., NAME=... Command.
  • Finally, we make a change in the reactive power control channel 2 at 5 seconds to 0.1 pu (e.g. 17.5 MVAr).

5) Configure the PSCAD™ output channels​

  • Add the following output channels to the PSCAD™ Node
PSCAD™ Node's Output field
OUTPUT, TITLE=smiby_POC_VOLT, VAL=V, NAME=i_v_poc
OUTPUT, TITLE=smiby_POC_P, VAL=PQS, NAME=i_p_poc
OUTPUT, TITLE=smiby_POC_Q, VAL=PQS, NAME=i_q_poc

OUTPUT, LOCATION=INV1, TITLE=termy_VOLT, CHANNEL_TYPE=V, NAME=i_v_terminal_1
OUTPUT, LOCATION=INV1, TITLE=termy_P, CHANNEL_TYPE=PQS, NAME=i_p_terminal_1
OUTPUT, LOCATION=INV1, TITLE=termy_Q, CHANNEL_TYPE=PQS, NAME=i_q_terminal_1

The above Commands:

  • Output the voltage magnitude at the point of connection (POC) to the grid and assign the name i_v_poc.
  • Output the active power at the POC and assign the name i_p_poc.
  • Output the reactive power at the POC and assign the name i_q_poc.
  • Output the voltage magnitude at the generator terminals and assign the name i_v_terminal_1.
  • Output the active power at the generator terminals and assign the name i_p_terminal_1.
  • Output the reactive power at the generator terminals and assign the name i_q_terminal_1.

6) Configure the Plot Node​

  • Double click on the Plot Node to open the configuration window.
  • Enter an output file name, such as Example 001 - PSCAD™ initialization from Static Node
  • Tick the Document (.pdf) and Interactive visualisation (.html) checkboxes for .pdf and .html output files.
  • Enter a plot title, such as Example (E001) | PSCAD™ initialization from Static Node.
  • In the Define Subplots tab:
    • Set the x-axis minimum to 4 and maximum to 10
    • Under Subplots select 1 page, 2 rows and 3 columns.
    • Click on the + to add a new subplot. 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_v_poc}}

example screenshot of configured subplots in plot node

7) Launch the Simulation​

  • Launch the simulation
  • The output plot should show a PSCAD™ simulation initialized from the static simulation results, specifically:
    • It should reach a steady state voltage magnitude of 1.00 pu at the connection point.
    • It should reach a steady state active power of 175 MW at the connection point.
    • It should reach a steady state reactive power of 0 MVAr at the connection point.

8) Review the results​

An example plot is shown below. We can see that the PSCAD™ simulation has been initialized to the desired values (1.00 pu, 175 MW and 0 MVAr) from the static simulation, with a Qref step to 0.1 pu (17.5 MVAr) at 5 seconds.

PDF output plot from the above step by step example

Revision history​

Version 7 | 20 May 2026​

Improvements
  • Replaced deprecated CONTROL Commands with CONTROL_VDIRECT, CONTROL_P and CONTROL_Q in PSS®E Static Node 1009.
  • Updated names for Internode Variables as per latest gridmo standards.

Version 6 | 15 December 2025​

Improvements
  • Added Action Nodes.
  • Replaced the deprecated SETTLE_T Command with SETTLING_TIME Command in Plot Node 1011.

Version 5 | 17 June 2025​

  • Fixed spelling typos.

Version 4 (v1.4.15.6) | 23 July 2024​

  • Updated Sticky Node helper text in example.

Version 3 (v1.4.12) | 15 April 2024​

  • Added PowerFactory Static and Dynamic Nodes to this example.

Version 2 (v1.3.1) | 27 June 2024​

  • Added PSCAD™ Nodes to this example.

Version 1 (v1.2.2) | 16 March 2023​

  • First release of example file.