In a hydro power plant, there are two identical generators connected to the transmission grid through a 6km, 33kv feeder line. The generator ratings are 6.6KV, 7.2MW,0.85PF,8400KVA. currently, there is a malfunction whereby one generator trips frequently on voltage protection as a result of grid voltage fluctuation since it can not adjust its voltage as the grid voltage varies. what could be the possible cause of this problem? since the AVR settings are still unchanged.
Hello Jaccob,
It could be due to different relay settings for voltage relays connected to generators.
Thank u so much, Mr. Gurung. However, at first we found out that one generator was set 108% while the other was set to 112% voltage protection. This was corrected and all are now set to 112% though the problem still persists. could there be any more possible cause/causes?
It could be if the voltage fluctuation lies beyond the relay settings.
If you are specifying the PF, maybe the generator acts as a PQ generator, and therefore, cannot provide the desired Q in order to maintain the voltage at the respective Bus? AVR will act only when you set it to a V-controlling genrator (PV bus)
Hi all, thank you so much for all your answers. However let us think like this:- If the VT leads at the protection relay terminal are interchanged. Then what are the probable effects?
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