It is not possible to control the system voltage when the generator is connected to an infinite bus. In this instance, it is necessary for the voltage regulator to regulate the reactive power output that is supplied by the generator. There are two methods for regulating the reactive power output.
- Power Factor Regulation
- KVAR Regulation
Power factor (PF) determines the relationship between true power and apparent power. The true power is also known as the active power. The apparent power is also called kVA. The true power (kW) is the work that is done on the load by the engine.
The true power determines the amount of power that is available for the load to do work. The apparent power (kVA) is the total power that is produced by the generator. Power factor can be calculated by using the following formula.
PF = KW / KVA,
KW - kilowatts
KVA - Kilo-Volt-Ampere
KVAR stands for Kilo-Volt-Ampere-Reactive, which is the unit of measurement for reactive power.
Note: The generator does NOT control power factor. Power factor is determined by the load.
The voltage regulator can be used with an external device (KVAR/PF controller) in order to control one of the output parameters of the generator such as KVAR or PF.
When the voltage regulator is in the power factor mode, the generator produces a constant power factor regardless of the real power output of the generator.
In this case, the reactive current will change when the real power output of the generator changes. A 5 Amperes current transformer is necessary for any mode of operation to work.
When the voltage regulator is in the KVAR operating mode, the generator produces a constant value of reactive power (KVAR) regardless of the real power output of the generator. In this case, the power factor of the generator will change when the real power output of the generator changes.
A 5 Amperes current transformer is necessary for any mode of operation to work.