In the power system, the existingreactive power compensation equipmentincludes two types: static reactive power compensation devices and dynamic reactive power compensation devices. The former includes shunt capacitors and shunt reactors, while the latter includes synchronous compensators (condensers) and static var systems (SVS).
The functions of shunt reactors are:
1) They can weaken the capacitive effect, limit the rise of power frequency voltage and switching overvoltage. The disadvantage is that for shunt reactors with fixed capacity, when the line transmission power approaches the natural power, the line voltage may be excessively reduced, and additional active power loss is caused. However, if they are switched off, the line may in some cases produce unacceptable overvoltage due to loss of compensation;
2) They absorb capacitive current, compensate capacitive reactive power, and achieve reactive power balance in the system.
The improvement method is to adopt controllable reactors, which change the saturation level (i.e., operating point) of the iron core by means of DC excitation in the control circuit, thereby achieving smooth adjustment of reactive power output.
