Methods of Voltage Control in Electrical Power Systems

The term voltage control refers to the methods of controlling variations of voltage at the consumer’s terminals.

There are various methods of controlling voltage. Given below is a list of a few methods for voltage control.

  • Auto-transformer tap changing: In this case an auto-transformer is used for control voltage.
  • Booster transformers: A Booster transformer is one that is used towards the end of a power line to raise the voltage to the desired value.
  • By controlling excitation: Whenever the load on the power system changes, there is voltage drop in the synchronous reactance of the armature and the terminal voltage of the alternator also changes due to this change of voltage drop. In order to maintain a constant voltage of the alternator, field current of the alternator is to be changed in accordance with the load. This method of controlling voltage is termed as voltage control using excitation method.
  • By synchronous condenser: The synchronous condenser an over-excited synchronous motor running on no-load. Synchronous condensers are very often used for doing voltage control.
  • By using tap changing transformers: By using tap changing transformers, the voltage in the line is adjusted by changing the secondary EMF of the transformer by varying the number of secondary turns.
  • Induction regulators: An induction regulator is identical to an induction motor with the difference that the rotor is not allowed to rotate continuously.

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