The electrical equipment of the power system will produce active power and reactive power when in use. Active power converts electrical energy into mechanical, thermal, chemical, or acoustic energy, while reactive power converts electrical energy into another form of energy, such as electrical energy occupied by electromagnetic components to build up a magnetic field.

Alternating current is phased, in the AC circuit, the phase of the capacitor is 90 degrees ahead, the phase lag of the inductor is 90 degrees, the capacitance and inductance can complement each other and stabilize the power supply quality, improve the power supply efficiency, reduce the loss of the role of the reactive power compensation by connecting the device with capacitive power load and the inductive power load in parallel in the same circuit. The electrical equipment of the power system is usually inductive, so the reactive power compensation can be achieved by properly paralleling the capacitors.

Automatic compensation device

At present, the mainstream compensation method is automatic compensation, which uses the reactive power compensation controller to switch the capacitor, as shown in the figure below.