Explain the behavior of generator when operating alone and operating parallel with grid.

Explain the behavior of generator when operating alone and operating parallel with
grid.
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1 Answer

Answer :

Generator operating alone.
a) The power factor of generator depends on load power factor.
b) The terminal voltage decreases when generator is loaded.
c) Governor decides the frequency of generator.
d) Increase in excitation increases the terminal voltage of the generator.

Generator parallel with grid.
a) If we increase the steam input to the generator the frequency of the generator will not change. It will remain practically constant as same as grid frequency. That is grid decides the frequency of the generator.
b) Increase in the excitation will not increase the terminal voltage. Instead the reactive power out put of the generator increases. This reactive power supplies for the magnetizing current of motors, transformers and etc.
c) Increase in the steam input increases the active power of the generator.
d) If generator is under excited it will draw leading reactive current from the grid.
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