The dynamic and static methods of the reactive compensation device are both artificial. Now it is recognized that the capacitor cabinet of contactor switching is the static compensation, while the capacitor cabinet with thyristor switching and SVG with power electronic devices as reactive power compensation are the dynamic compensation. SVC is also a dynamic compensation category. So-called dynamic compensation can use electronic devices to switch capacitor banks at zero crossing, so as to compensate the reactive power of the system in real time. The capacitor bank of contactor switching can not be done because of the switch of contact electromagnetic switch.