Correct Answer - Option 3 : Synchronous motor
The power-transfer capability of EHV transmission lines can be increased by maintaining the loaded voltage within specified limits.
The following methods are used for maintaining the voltage within limits:
- Shunt capacitor bank
- Shunt reactors
- Synchronous condensers
- Static VAR compensators at heavy loads
- Series compensation
A synchronous condenser is not a static compensation. A synchronous condenser is a synchronous motor running at no load and taking leading current.
A synchronous condenser is an overexcited synchronous motor, which draws leading currents from the system and hence compensates for lagging vars. It is used as a reactive power compensator in some systems for power factor correction purposes.