Skip to main content

Warning 102 | [PSCAD™] | Plot step is abnormally large


Relevant software:

PSCAD™


Emitted message:

The plot step detected in PSCAD is very large - it has a lower resolution than a typical PSSE/PowerFactory Dynamic simulation. This can cause result aliasing - the hiding of higher frequency oscillations or rapid control mode switches. PSCAD recommend 250 us plot step by default.

Description:​

This warning indicates that the plot step configured in your PSCAD™ model is larger than the typical value recommended for electromagnetic transient (EMT) studies.

danger

This warning indicates there may be an issue in your PSCAD™ model which may cause high-frequency oscillations or rapid control mode switches to be missed or misrepresented in your simulation results.

Possible impact:​

  • Result aliasing - high-frequency oscillations or rapid control mode switches may be hidden or misrepresented in connected plots (as can be seen below).
  • Voltage oscillation rejection test results look very low resolution.
Screenshot of PSCAD™ oscillation rejection at low and high resolution

Potential fixes:​

To resolve this warning, consider:

  • Changing the plot step in your PSCAD™ simulation to the PSCAD™ recommended value of 250 μs (microseconds), or
  • Changing the plot step to at most 1000 μs (as this is the typical timestep of PSS®E or PowerFactory dynamic simulations which you might be benchmarking against).

After changing, consider rerunning any simulations which have high frequency responses (like voltage oscillation rejection testing or fault ride-through testing) with the new plot step.

Screenshot of large PSCAD™ plot step