10kV配电线路感应雷过电压波形特征实测分析

Waveform Analysis on Characteristics of Lightning Induced Overvoltages on 10kV Overhead Distribution Lines

为获取配电线路上感应雷过电压数据,研究其波形特征,以期指导架空配电线路雷电防护,该文利用线路过电压在线监测系统,对云南省丽江市华坪县某10kV配电线路上感应雷过电压进行了实测,并对其波形特征和影响因素进行了分析。2021年6至8月份,系统记录了该线路雷雨季节内42次雷电感应过电压数据。测得感应雷过电压波形大体表现出3个过程:包括在初始负峰值之前的缓慢升高,随后是快速极性反转以及后续的衰减振荡,其中最后一个过程值得注意。严格来说,所有记录的电压都是双极性的,但实际情况下普遍认为只有一个半周期具有重要影响。实测感应雷过电压波形参数受不同定义标准影响,可能与标准雷电冲击电压(1.2/50μs)有很大不同。依据Piantini提出的感应电压分类标准,单极性波形占总数的19%,大部分数据呈正极性,波头时间平均值、中值分别为14.5μs、13.2μs。双极性波形占总数的81%,其中,63%第一个半周期是负极性的,在91%的情况下,电压峰值出现在第一个或第二个半周期。

In order to obtain the induced lightning overvoltage waveforms on distribution lines and study the characteristics of the waveforms to guide the lightning protection of overhead distribution lines,this paper used the line overvoltage online monitoring system to induce induction on a 10kV distribution line in Huaping,Lijiang,Yunnan Province.The lightning overvoltage was measured,and its waveform characteristics and influencing factors were analyzed.From June to August 2021,the system recorded 42 lightning-induced overvoltage data of the line.The measured lightning induced lightning overvoltage waveform generally showed three processes:including a slow rise before the initial negative peak,followed by a rapid polarity reversal,and subsequent oscillation attenuation.In the last process,it is noted that all recorded voltages are bipolar,but,it is generally believed that only one semi-cycle has an important effect.The measured lightning induced lightning overvoltage waveform parameters are affected by different defined standards,and may be very different from the standard lightning impulse voltage(1.2/50μs).According to Piantini's classification standard for induced voltage,unipolar waveforms account for 19%of the total,and most of the data are positive.The average and median wave head time are 14.5μs and 12.1μs,respectively.Bipolar waveforms accounted for 81%of the total,of which 63%have negative polarity in the first half cycle.In 91%of the cases,the voltage peak appears in the first or second semi-cycle.