Introduction:
- Feeder voltage regulators are extensively used to regulate or control the voltage in the feeder circuit
- The voltage regulator is used to maintain the voltage of each feeder separately to maintain a reasonably constant voltage at the point of utilization
- The induction voltage regulator is the simplest and most commonly used electrical machine to regulate the voltage in the feeder circuit
- It is a type of an electrical machine in which the output voltage may be varied from zero to a certain maximum value
- In induction type voltage regulator, the primary winding is a high voltage winding which is connected across the circuit to be regulated and low-voltage winding is connected in series with the circuit
- An induction Voltage regulator is essentially a constant voltage transformer, one winding of which is called primary winding can be moved w.r.t. the other which is called secondary winding, thereby obtaining a variable secondary voltage.
- The primary winding is connected across the supply while the secondary winding is connected in series with the line whose voltage is to be controlled.
- When the position of one winding is changed w.r.t the other, the secondary voltage injected into the line also changes.
Types of Voltage regulators:
There are two types of Voltage regulators
- Single phase voltage regulators
- Three phase voltage regulators
Single phase Voltage Regulator:
Definition:
- A single-phase induction regulator has a (primary) excitation winding, connected to the supply voltage, wound on a magnetic core which can be rotated.
- The stationary secondary winding is connected in series with the circuit to be regulated.
Construction:
- The single-phase induction regulator consists of primary winding (stator) and secondary winding (rotor).
- The secondary winding is connected in series with the line whose voltage is to be controlled.
- The rotor doesn’t allow to rotate continuously but its position can be adjusted by means of a small motor or worm gear.
- When the position of the secondary winding is changed with respect to primary winding, the injected voltage in the line also is changed.
- The primary windings are placed in slots in the surface core of the laminated cylindrical core since it has to carry small currents and has small conductor area.
- The rotor of the regulator consists compensating windings also called the territory windings.
- The magnetic axis of the compensating windings is always 90º away from that of the primary windings, to neutralize the harmful series reactance effect of the secondary.
- The secondary windings connected in series with the outgoing line are housed in the stator slots, due to its large conductor area.
- The single-phase voltage regulator does not cause any phase shift.
Three Phase Voltage regulator:
Definition:
- The three-phase induction regulator can be regarded as a wound induction motor. The rotor is not allowed to turn freely, and it can be mechanically shifted by means of a worm gear.
Application of Induction Voltage Regulators:
- An induction regulator is an alternating current electrical machine, somewhat similar to an induction motor, which can provide a continuously variable output voltage.
- The induction regulator was an early device used to control the voltage of power system networks, mainly used in primary distribution.