This example evaluates the flicker coefficients for the various operating conditions specified in Table A.1 - Annex A of the IEC/TR 61000-3-7 (Edition 2.0). Although the intention of this example is the demonstration of the correct operation of the Flicker meter tool (based on standardised data sets), it can also be used for the general understanding of computing the short term flicker coefficient based on instantaneous values data while using PowerFactory. The project contains the following components:

- a DSL (dynamic) model that generates voltage curves as specified in the fore mentioned Table A.1. The DSL model is named "Voltage reference model" and contains four parameters: Unom (rated voltage), Fnom (rated frequency), FluctuationRate (as described in Table A.1) and VoltageFluctuation (as described in Table A.1). This model allows the generation of standardised curves. Alternatively, the Flicker meter tool allows any kind of instantaneous data to be used e.g. obtained via a measurement or via a specific simulation of a power system. The purpose of this model is for benchmarking reasons only.

- a simple 400 V exemplary system containing a voltage source (feeding the previously generated voltage curves) connected to a three phase load 3*60W.

- a preconfigured EMT simulation with a time step of 0.1 ms

- an optional Python script "FlickerEvaluation" that automatically does the following: (a) reads one row from table "FlickerEvaluation.IntMat" stored inside the script, namely one set of parameters FluctuationRate and VoltageFluctuation; (b) sets this parameter set to the model "Voltage reference model"; (c) runs an EMT simulation (by default for 10 minutes); (d) after completion of the simulation it executes the Flicker meter tool (by default it uses the phase A to ground voltage) in order to obtain the flicker coefficient Pst; (e) writes the value of Pst to the corresponding row of the parameter set within the third column of the table "FlickerEvaluation.IntMat"; and (f) re-executes steps (a) to (e) for every remaining row within the table.

Prerequisites - the following PowerFactory additional modules are needed to run this example: EMT Simulation, Power Quality and Harmonics, (optional) Scripting and Automation

Instructions:

- Import and activate the project attached to this FAQ

Option 1 - Manually perform the analysis

- Activate study case "SC01 - Flicker Evaluation (manual)"

- Locate the model "Voltage reference model" and open its dialog; Set accordingly the parameters FluctuationRate and VoltageFluctuation to specific values.

- By default the dynamic simulation records phase A to ground voltage. If the flicker of a different quantity is targeted, then make sure to add this result to the dynamic simulation Result file (ElmRes).

- Execute an EMT simulation for a duration Tsim equal to the flicker observation period plus 5 seconds (e.g. if an Observation period of 1 minute is targeted, then run a simulation for 65 seconds)

- After successful execution of the simulation, open the Flicker meter tool. Configure it to calculate Pst for the targeted variable and for the specified Observation period.

- Execute the flicker calculation and read the Pst value from the Output window.

- Re-run the process for different values of parameters FluctuationRate and VoltageFluctuation.

Option 2 - Use the automated procedure via the Python script

- Activate study case "SC01 - Flicker Evaluation (manual)"

- From the single line diagram, click on the button "Flicker Evaluation"

- Execute the script. The script will run a single case, preconfigured for case number 28 (Fluctuation Rate at 2400 changes/min and Voltage Fluctuation at 0.77%)

- After the script is executed the third column within the table "FlickerEvaluation.IntMat" stored inside the script contains the resulting Pst values.

- Re-run the script but with different script settings e.g. CaseSelection = 0 (all cases) and ObservationPeriod = 1. Check the Pst resulting levels in the table "After the script is executed the third column within the table "FlickerEvaluation.IntMat" stored inside the script contains the resulting Pst values." .

Notes:

- if using any of the parameter sets from Table A.1 - Annex A of the IEC/TR 61000-3-7, each case will result in a Pst value close to 1. An allowed tolerance of +/-5% is specified within the standard (IEC 61000-4-15 Ed2.0).

- slightly different results will be obtained for Pst if changing the simulation settings e.g. different time step of the EMT simulation.