Hi, can someone please tell, how to calculate the Rate (MVA) in Branch -> AC Lines

answered 2020-06-19 05:26:37 -0500

lmcqueen
66 ●32 ●35 ●37

Rate A (Normal Rating) is based on the ampacity/thermal rating of conductor dependent on the following factors: ambient temperature, wind speed, permissible sag, etc. Rate B (Long Term Emergency Rating) is the permissible loading in the conductor for a period of time when a contingency occurs.

When you are trying to verify how PSS/E arrived with the percent loading of the line after performing a load flow solution, you have to take into account the pre- or post-contingency voltage.

answered 2020-06-19 03:01:47 -0500

perolofl
3272 ●1 ●8 ●18

Rate = In * Vbase * sqrt(3), Where In is rated current [kA] and Vbase is bus base voltage [kV]. E.g. a 500 kV line rated 1.5 kA has the rating 1299 MVA.