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Hello,
We are doing a process simulation of a Turbine Generator for a client who will use it for Operator training purposes. My question is, when the generator is synchronized with the grid, the frequency is fixed to whatever the grid frequency is. Also, the generator terminal voltage is basically fixed to the grid voltage. in our model, Generator voltage is controlled by the exciter before synchronization, and after sync, the exciter controls VArs. However, in the actual process, the Mill uses automatic voltage control even after synchronization. (They can also run in Automatic Var control, but they don't use it). Since theoretically the voltage should be locked to grid frequency, what is the AVR doing? I know from looking at the actual process that the Generator voltage was less than the Voltage at the utility tieline. I also watched the exciter voltage vary several volts up and down a couple of times a second in a range of about +-5 volts.
My question is, where does this voltage difference come from? is it just imperfections in the equipment or voltage drops in the Mill distribution system? The other client we are doing work for also has AVR running after synchronization, Since we are trying to model this behavior, can someone tell me why AVR is necessary after synchronization, and where the voltage variations come from that necessitate the use of AVR after sync?
Please understand that I am in no way questioning the use of AVR after sync, it seems to be normal, I'm only trying to understand where these voltage variations come from so we can introduce them into our model.
Thanks
We are doing a process simulation of a Turbine Generator for a client who will use it for Operator training purposes. My question is, when the generator is synchronized with the grid, the frequency is fixed to whatever the grid frequency is. Also, the generator terminal voltage is basically fixed to the grid voltage. in our model, Generator voltage is controlled by the exciter before synchronization, and after sync, the exciter controls VArs. However, in the actual process, the Mill uses automatic voltage control even after synchronization. (They can also run in Automatic Var control, but they don't use it). Since theoretically the voltage should be locked to grid frequency, what is the AVR doing? I know from looking at the actual process that the Generator voltage was less than the Voltage at the utility tieline. I also watched the exciter voltage vary several volts up and down a couple of times a second in a range of about +-5 volts.
My question is, where does this voltage difference come from? is it just imperfections in the equipment or voltage drops in the Mill distribution system? The other client we are doing work for also has AVR running after synchronization, Since we are trying to model this behavior, can someone tell me why AVR is necessary after synchronization, and where the voltage variations come from that necessitate the use of AVR after sync?
Please understand that I am in no way questioning the use of AVR after sync, it seems to be normal, I'm only trying to understand where these voltage variations come from so we can introduce them into our model.
Thanks