发电厂和变电站接地设计安全判据的探讨

Discussion of Earthing Design Safety Criteria for AC Power Plant and Substation Grounding System

人身安全和设备安全是发电厂和变电站接地设计的主要目的。国内接地设计标准《GB 50065-2011:交流电气装置的接地设计规范》和国际接地设计标准《IEEE Std 80-2000 IEEE Guide for Safety in ACSubstation Grounding》中关于这两个接地系统目的的安全判据有所不同。通过对两者的分析,给出了两个标准对于人身安全判据的适用范围。同时,指出了两个标准对于设备安全判据的局限性,并根据发电厂和变电站设备绝缘水平、布置及运行的实际情况,首次提出宜采用最大相对地电位差作为接地系统中设备安全判据的新思路。对于大面积或者土壤电阻率较高的发电厂和变电站来说,应用此判据可大幅提高经济性。

Safety for person and equipment is the main purpose of power plant and substation grounding system design.The safety criteria defined in the domestic grounding design standard ＂GB 50065-2011： Code for design of ac electrical installations earthing＂ and the international grounding design standard ＂IEEE Std 80-2000： IEEE Guide for Safety in AC Substation Grounding＂ are different.According to the analysis of them,application scope for personal safety criterion is presented.At the same time,limitation of equipment safety criterion in these two standards is pointed out.And based on the equipments’ insulation level,arrangement and actual running situation in the power plant and substation,it is recommended for the first time to use the maximum relative potential rise inside the power plant or substation grounding system as the equipment safety criterion.For large area or high soil resistivity power plant and substation,it can greatly improve the economical efficiency.