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Warning 108 | [PSS®E] | Line impedance abnormally low


Relevant software:

PSS®E


Emitted message:

Detected abnormally low line impedance
tip

If your PSS®E Dynamic results appear stable you can ignore this warning.

Description:​

This warning indicates that the PSS®E model contains a transmission line with an abnormally low impedance value.

danger

Abnormally low line impedances may cause numerical instability in static and dynamic simulations.

Possible impact:​

  • We've seen cases where extremely low line impedances can cause numerical instability in static and dynamic simulations in PSS®E, such as large spikes of reactive power during dynamic simulations.

Potential fixes:​

  • Open the PSS®E case file and inspect the line specified in the warning. A minimum Line R (pu) value of 0 and a minimum Line X (pu) value of 0.0001 is recommended.