Shunt reactor used in capacitive charging current compensation circuit, limit system of power frequency voltage and operation over-voltage, thereby reducing the insulation of the system level, To ensure the reliable operation of the line. With the continuous expansion of city in our country and the city power grid renovation, overhead line transmission replaced gradually by underground cable transmission, Make the transmission network of capacitive charging current increases sharply, in order to reduce the system power frequency voltage and insulation level, the rise of guarantee system of safe and reliable Operation and quality of power supply of the city, in a high pressure and ultra-high voltage, long-distance transmission system is widely used in the shunt reactor in than in the urban power distribution grid The application of it.