Pre RVC Event Voltage

[eRicC]

Hi there,

There is a compliance requirement in solar farm to measure a RVC event by calculating the percentage change of "dynamic voltage change" against "pre-disturbance voltage" (i.e. "dynamic voltage change"/"pre-disturbance voltage").  

ION9000 shall be installed while there is a question about the algorithm to meet the RVC monitoring requirement.

Understood that there is Delta Umax under Sag/Swell module which can be used as the "dynamic voltage change".  And under the current RVC algorithm in sag/swell module, the pre-disturbance voltage shall be the 100/120 cycles RMS mean before the RVC.  However, that pre-disturbance voltage is not available as an output register so it is not a straightforward extract to calculate the required percentage change.

Because of this, as the voltage measurement (under normal Power Meter module) is an average of 1024 sample and updating per second, I'm thinking of averaging the 5 second of voltage in sliding window basis and capture that as pre-disturbance voltage when RVC status changed to false.

Hence, may I confirm if my understanding is correct that voltage measurement is an average of 1024 sample such that averaging the 5s value could meet the 100/120 cycles RMS?

Or otherwise what's the recommendation to extract that pre-disturbance voltage?

Thanks.

Regards,

[Charles_Murison · Accepted solution]

Hello @eRicC ,
The meter's 1024 samples are done per cycle. In RVC, the 100/120 is half cycles, so 100/120 is approximately 1 second. You are correct that the sag/swell module does not provide the mean voltage before the event starts. The 5 second SWD module would likely be close if the voltage is stable. Not exact, but would be close.

I do not know of a way to extract the pre-event mean voltage.

Regards,

Charles