一起110 kV母差保護誤動事件分析及改進
黃楊明，任欣元，莫靖，李強
廣東電網公司佛山供電局，廣東 佛山 528000
摘 要：分析了某220kV變電站發生的一起110kV母差保護誤動事件，得出了本次誤動的根本原因在于外部故障切除后，母差保護立刻退出電流波形識別閉鎖判據這一邏輯缺陷。考慮到電流在電流互感器(CT)飽和后每一過零點都有一段3～4ms真實傳變區，提出過零點重啟波形識別判據，直到波形識別出CT飽和消失，以解決區外故障切除后，在衰減過程中的非周期分量影響下，母差保護誤動問題。
關鍵詞：母差保護；CT飽和；誤動；波形識別；非周期分量
中圖分類號：TM773 文獻標識碼：B 文章編號：1007-3175(2013)02-0027-04
Analysis and Improvement of 110 kV Busbar Differential Protection Misoperation Accident
HUANG Yang-ming, REN Xin-yuan, MO Jing, LI Qiang
Foshan Power Supply Bureau, Guangdong Power Grid Corp, Foshan 528000, China
Abstract: Analysis was made to the accidental operation of a 110 kV busbar differential protection in certain 220 kV substation. The fundamental reason of the accidental operation was the defective logic that busbar differential protection immediately exited the current waveform recognition locking criterion after the removal of external faults. Considering that after the current transformer (CT) saturated in each zero crossing, the current has a 3 to 4 ms real transmission area, this paper put forward that the current waveform recognition criterion was restarted in each zero crossing until the CT saturation disappeared, to solve the problem of busbar differential protection maloperation under the influence of the aperiodic component in the attenuation process after the removal of external faults.
Key words: busbar differential protection; current transformer saturation; misoperation; waveform identification; aperiodic component
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