石化企业6(10)kV系统中性点接地方式与供电可靠性探讨

DISCUSSION ON THE RELIABILITY OF NEUTRAL POINT GROUNDING MODES AND POWER SUPPLY OF 6(10) KV SYSTEM IN PETROCHEMICAL ENTERPRISES

探讨了石化企业6(10)k V系统中性点常用接地方式的主要优缺点,研究了石化企业6(10)k V系统中性点接地方式的选择与供电可靠性的关系,得出了石化企业6(10)k V系统中性点宜采用电阻接地方式的结论。文章的创新点及重点之一是中性点经过电阻接地方式必要时可以转换为不接地方式,使保护得以灵活设置,可以实现准确选线。另一重点是研究了接地故障时接地电流的分布,以便准确地选择接地保护对应的电流互感器,避免出现似是而非的错误。

This paper discusses the main advantages and disadvantages of the commonly used neutral point grounding mode in 6(10)kV system in petrochemical enterprises.It also researches about the relationship between the selection of different grounding modes and reliability of power supply.Then the paper arrives at the conclusion that the neutral point of the 6(10)kV system in petrochemical enterprises should adopt the resistance grounding mode.One of the important and innovative points in this paper is that the resistance grounding mode of the neutral point could be turned to un-grounding mode when necessary,so that grounding protection can be set flexibly and accurate grounding loop can be achieved.Another focus is the research on the distribution of grounding current during grounding fault,which contributes to the selection of current transformer corresponding to the grounding protection accurately so that plausible errors could be avoided.