We are synchronizing 4MW and 12MW turbine generators. First time when we built up voltage in 4MW generator, its AVR was showing negative value of KW, KVAR and PF at that time PT sensing phase sequence was BYR. after that I changed phase sequence and made RBY, again applied load on the system and AVR was showing negative value of KVAR and PF. Again I changed phase sequence and made it YRB, now AVR is showing negative value of KW.

Please guide me what should i do?

Your response would be highly appreciated.

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Dear Jeet,

1- It is sensitive matter be careful. The phase marketing at generator terminal RYB and the PTs installed should be the same.

2- If KVAr, KW, PF are negative before synchronizing! definitely your connection of CTs fitted at phases are either reverse connected ie S1-S2 are reversed or direction of CT K-L is reversed. Just change the connections of CTs per phase.

If these are correct then reverse the polarity of your instruments.

3- I shall advise not to attempt to synchronize without sufficient expertise and knowledge.

Regards

 

There is a table on the commissioning manual of the EX (there is one if the EX is an EX2100 from GE- GEH) that will help to troubleshoot the problem that you described.

 

Dear Sir,

Thanks for your response.

I made reverse connection of CT and PT sensing sequence is as BYR and now AVR is showing all values in positive.