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Hi,
Our grid code mandates that all generators must have the capability to supply/absorb MVar within the range of 0.85 lagging to 0.9 leading. Supplying/absorbing MVar beyond these power factor limit can be subject to remuneration thus we want to operate our generators beyond these power factor as long as we will operate with the capability curve. However during testing, when we raise the AVR voltage setter to raise to supply of MVar, the generator terminal voltage also increases from 14 kV to 14.4 kV. We stop at 14.4 kV because the standard says that the safe operation for generator should be 95%-105% of terminal voltage (100% Rated = 13.8 kV). But when the our voltage is 14.4 kV the power factor is 0.95 lagging which means it is still inside the "free zone" and our objective is to operate lower than 0.85 lagging but the 105% limit hindered us from doing this.
Can someone provide me recommendations on how are we going to operate lower than the 0.85 lagging or 0.9 leading power factor without hitting the 95%/105% generator terminal voltage limit. Can reconfiguring the AVR solve this concern? Our AVR is ABB Unitrol F. Or will changing the generator stepup transformer tap changer have an effect? Our off load tap changer is set at tap 2 (224.25/13.8 kV). Our grid voltage is maintained at 230 kV.
Thank you in advance.
Our grid code mandates that all generators must have the capability to supply/absorb MVar within the range of 0.85 lagging to 0.9 leading. Supplying/absorbing MVar beyond these power factor limit can be subject to remuneration thus we want to operate our generators beyond these power factor as long as we will operate with the capability curve. However during testing, when we raise the AVR voltage setter to raise to supply of MVar, the generator terminal voltage also increases from 14 kV to 14.4 kV. We stop at 14.4 kV because the standard says that the safe operation for generator should be 95%-105% of terminal voltage (100% Rated = 13.8 kV). But when the our voltage is 14.4 kV the power factor is 0.95 lagging which means it is still inside the "free zone" and our objective is to operate lower than 0.85 lagging but the 105% limit hindered us from doing this.
Can someone provide me recommendations on how are we going to operate lower than the 0.85 lagging or 0.9 leading power factor without hitting the 95%/105% generator terminal voltage limit. Can reconfiguring the AVR solve this concern? Our AVR is ABB Unitrol F. Or will changing the generator stepup transformer tap changer have an effect? Our off load tap changer is set at tap 2 (224.25/13.8 kV). Our grid voltage is maintained at 230 kV.
Thank you in advance.