Question about LTC Transformers

[user1011]

I'm performing Reactive power study for a solar plant to determine compliance with FERC 827 and quantify if there is a need for additional reactive power compensation device. Should I include in the study the effect of LTC of the main transformer on the reactive power flow at the POI?

 

[waross]

It depends.
LTC adjusts the voltage.
Voltage adjustments tend to vary the reactive current.
Due diligence suggests considering the effect of LTC operation.
The effect may be significant or it may be negligible.
It depends on information not given.

 

[JJ_Roy]

Yes. Compliance with FERC 827 requires the reactive power capabilities to met at the high side of the station transformer. Some interconnections requirements say it's at the point of interconnection (POI).

As warross noted, the LTC could have a significant impact....

I'd check with the interconnecting utility (or system operator) as there is probably some sort of planning procedure that dictates how you determine the reactive capability.