小電阻接地系統線路零序保護拒動原因分析
武冠英
(無錫供電公司，江蘇 無錫 214000)
摘 要： 根據小電阻接地方式下的零序保護原理，介紹了小電流接地系統零序保護不動作的原因，分析了一起線路零序保護由于存在保護死區致使故障范圍擴大的案例，通過對如何防止零序保護拒動問題進行探討，提出了相應的反事故措施及其對策，為防止線路零序保護死區故障，建議其零序電流采用三相電流互感器合并而成，并制定有針對性的保護定值調整方案，為設備安全穩定運行提供保障。
關鍵詞： 小電阻接地；線路保護；零序保護；死區；保護拒動
中圖分類號：TM645 文獻標識碼：B 文章編號：1007-3175(2014)07-0036-05
Zero Sequence Protection Action Refusal Cause Analysis of Small Resistance Grounding System
WU Guan-ying
（Wuxi Power Supply Company, Wuxi 214000, China）
Abstract: According to the zero sequence protection principle under the small resistance grounding method, this paper introduced the zero sequence protection action refusal cause of small resistance grounding system and analyzed a case of line zero sequence protection due to existing of protection dead zone leading to fault range expansion. This paper discussed how to prevent the zero sequence protection action refusal problem from taking place and raised the corresponding fault countermeasures. In order to avoid dead zone faults of line zero sequence protection, this paper suggests that the zero sequence current should be merged in three-phase current transformer and the protection setting value adjustment scheme should be set down to provide insurance for safe and stable operation of equipment.
Key words: small resistance grounding; line protection; zero sequence protection; dead zone; protection action refusal
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