Research And Application Of The Limit Measures Of Single-phase Short-circuit Current In 500kV JiLantai Substation

In recent years, with the rapid development of national economy and the growing use of electrical load, and the continuous expansion of network scale, the relationship between power grid was becoming more and more closely,which made the short-circuit current in power system increasing. In the EHV transmission system, the main transformer always use auto-transformers with neutral grounding, which made the side of the bus 220 k V single-phase short-circuit current increase even close to or exceed the breaking capacity of the circuit breaker. So it is necessary to take certain measures to limit the short-circuit current. Based on 500 k V Ji Lantai Substation neutral point of the installation of small reactors project, in the paper specifically works were made as follows: Firstly, this paper described the background, and explained the necessity of taking measures to limit the flow in Ji Lantai area, and compared several commonly used measures to limit the flow of the characteristics and application scope. Secondly, it analysed the principle of neutral point of adding small reactance to limit current,and combined with the practical engineering showed the validity of short-circuit current limit in Ji Lantai 500 k V substation main transformer neutral point of adding small reactance. Finally, it researched 500 k V Ji Lantai Substation’s frequency overvoltage and switching overvoltage of the neutral point, studied the related parameters of power and the main transformer arrester and protective gap, as while as the main transformer neutral reactor’s technical parameters. The project was put into operation in March 2015,and neutral grounding via small reactance was normal.