In the power grid, voltage quality is closely related to reactive power compensation. A reasonable configuration of the reactive power compensation device can improve the voltage quality. Reactive power compensation devices improve voltage quality by reducing the loss of voltage in the line. The reactive power compensation device can reduce the electricity cost of the power user by increasing the power factor, and can realize the economic benefit of the power user very significantly. At the same time, the power generation, power supply and power consumption of power users are relatively high. The poor quality of power supply is also partly due to the low power factor of the power users and the large reactive power consumed. The reactive power compensation device can improve this.