Study on the neutral reactor of shut reactor of insulation level for UHV transmission lines

In recent years, with the continuous development of power technology. China has been completing its own backbone network by developing 1000kV AC power grids and 800kV HVDC transmission system. It is commonly use neutral reactor of shunt reactor to prevent the secondary arc current caused by the single phase short circuit. In the actual commissioning test on the 1000kV UHV AC Demonstration Project. UHV equipment can work normally but the neutral reactor often occurs insulation fault. Therefore, it is of great significance to analyze the insulation level of the neutral reactor. This paper takes the Changzhi-Nanyang section of “the Jindongnan-Nanyang-Jingmen UHV project”as the object. Firstly, the ATP-EMTP is used to establish the UHV single transformation line model. Secondly, by analyzing the various influence of the secondary arc current after single phase short circuit, to obtain the regulation of secondary arc current and pick a proper value of the neutral reactor Finally, get the voltage of the reactor under three different situations, which is power-frequency over-voltage, operating over-voltage and lightning over-voltage, to evaluate the insulation level of the neutral reactor.