In power systems, the existingreactive power compensation equipment includesstatic reactive power compensation devices anddynamic 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, limiting the rise ofpower frequency voltage and switching overvoltages. Their disadvantage is that when the line transmits power close to the natural power, a fixed-capacity shunt reactor will cause the line voltage to drop excessively and create additional active power loss. However, if it is removed, the line may in some cases experience unacceptable overvoltage due to loss of compensation;
2) They absorb capacitive current and compensate for capacitive reactive power, achieving reactive power balance in the system.
The improvement method is to use controllablereactors, 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 ofreactive power output.
