Three phase shunt reactor is generally connected to 400KV or above electrical bus system for capacitive reactive power compensation of the power system and to control dynamic over voltage occurring in the system due to load rejection.
The shunt reactor should be capable of withstanding maximum continuous operating voltage (5% higher the rated voltage in case of 400 KV system) under normal power frequency variation without exceeding the top spot temperature of 150oC at any part of the shunt reactor.
The shunt reactor should be of gapped core type or magnetically shielded air core type. Both of these designs help to maintain the impedance of the reactor fixed. The impedance should be maintained at a constant value for avoiding harmonic current generated due to the system over voltage.
The shunt reactor has mainly core losses during its normal operating condition. So, care should be taken for minimizing the core losses during design.