10 kV配网电压互感器断保险故障分析及应对措施

Fault analysis and countermeasures for fuses blown of 10 kV distribution network PT

中性点不接地配电网中变电站发生的单相接地故障消失后易引发电压互感器(PT)铁磁谐振或低频非线性振荡等,导致PT熔断器频繁熔断,影响电力系统安全运行。为研究实际变电站PT断保险故障的基本规律及影响因素,文中统计了某供电公司1年内的35次断保险及PT故障,分析了一起实际变电站发生断保险故障前后的录波数据,对比各种故障诱因的仿真波形找出该变电站发生PT断保险的原因。最后在已经验证了的仿真模型的基础上,找出有效抑制该种故障的措施。研究表明:文中研究的变电站发生PT断保险的原因是单相接地故障消失瞬间激发的工频铁磁谐振。提出的抑制措施是针对实际运行环境优化参数的一次消谐装置以及改进的PT接法,抑制效果明显。

In the neutral ungrounded distribution network,the single-phase grounding fault and its disappearance can easily lead to potential transformer( PT) ferroresonance or low-frequency nonlinear oscillation,resulting in frequent PT fuses blown,affecting the safety of the power system. In order to study the basic rules and influence factors of PT fuses faults in actual substation,this paper analyzes 35 fuses and PT faults in a power supply company within one year. One certain recorded data before and after one fuse blown fault is analyzed,the cause of the PT fuses blown fault is found out through comparing with the simulation waveform of the fault. Finally,based on the verified simulation model,the measures to effectively eliminate the fault are found out. The research indicates that the reason for the PT fuses blown fault studied in this paper is the power frequency ferroresonance excited by the single phase grounding fault. The proposed suppression measure is a resonance eliminator with optimized parameters based on the actual working environment,and the method achieves a good result.