The main function of the reactor is to improve the operation of the power system, including improving the capacitance effect of no-load or load lines, improving the voltage distribution on long-distance transmission lines, and balancing the reactive power in the line during load. In addition, reactors can also be used to limit short-circuit currents, store electrical energy, suppress surge currents and harmonic currents.

In the power system, there are two wiring methods for reactors: series connection and parallel connection. Series reactors are mainly used to limit short-circuit currents, and can also be connected in series or parallel with capacitors in filters to limit high-order harmonics in the power grid. Parallel reactors are mainly used to change and improve the operating conditions of reactive power in power systems, such as absorbing charging capacitive reactive power from cable lines and preventing self excitation magnetic resonance phenomena when generators have long lines.