一起配电网铁磁谐振事件分析

Analysis of a Ferroresonance Event in a Distribution Network

单相接地故障消失引起的铁磁谐振是导致中性点不接地系统中PT熔断器熔断的最常见原因。文章针对云南某配电系统一次PT熔断器熔断事件的录波数据,结合铁磁谐振机理和类型,详细分析了事故经过及原因;利用快速傅里叶变换(FFT)进行频谱分析,确定了铁磁谐振的类型;最后分析了现场二次消谐装置未能正确动作的原因,并给出治理措施建议。

The ferroresonance caused by the disappearance of non-metallic single-phase ground fault is the most common reason for the fuse breakage of voltage transformer in neutral ungrounded system.Based on the recorded data of the fusing event of the primary voltage transformer in a distribution network of Yunnan Province,this paper analyzes the accident course and cause in detail on the basis of ferroresonance mechanism and equivalent circuit.The frequency spectrum was analyzed by fast Fourier transform(FFT)to determine the nature of the accident--a fundamental frequency ferroresonance event caused by the disappearance of a nonmetallic ground fault.Finally,combined with the actual production,gives the management measures.