配电网间歇性重燃电弧模型的建立与断续弧光接地故障特征分析研究  

Establishment of Intermittent Reignition Arc Model and Analysis of Intermittent Arcing Ground Faults in Distribution Network

作　　者：张彪 周申培[1,2] 吴细秀 侯博文[1,2] 侯慧 邱进 丁心志[3,4] ZHANG Biao;ZHOU Shenpei;WU Xixiu;HOU Bowen;HOU Hui;QIU Jin;DING Xinzhi(College of Automation,Wuhan University of Technology,Wuhan 430070,Hubei Province,China;State Key Laboratory of Power Grid Environment Protection(China Electrical Power Research Institute),Wuhan 430074,Hubei Province,China;School of Electrical and Electronic Engineering,Huazhong University of Science and Technology,Wuhan 430074,Hubei Province,China;Yunnan Electric Power Test and Research Institute(Group),Kunming 650217,Yunnan Province,China)

机构地区：[1]武汉理工大学自动化学院,湖北省武汉市430070 [2]电网环境保护国家重点实验室(中国电力科学研究院有限公司),湖北省武汉市430074 [3]华中科技大学电气与电子工程学院,湖北省武汉市430074 [4]云南电力试验研究院(集团)有限公司,云南省昆明市650217

出　　处：《电网技术》2024年第5期2207-2217,I0116-I0120,共16页Power System Technology

基　　金：电网环境保护国家重点实验室开放基金资助项目(GYW51201901085)。

摘　　要：电弧间歇性重燃是配电网单相接地故障最显著的特征。现有的电弧模型甚少考虑电弧间歇性重燃特性,导致无法精确描述断续弧光接地特征,进而影响继电保护动作。为此,论文提出一种间歇性重燃电弧模型的建立方法,并在此基础上对断续弧光接地故障特征进行了分析。弧道阻抗的随机变化是电弧间歇性重燃的重要标志,故论文重点围绕弧道阻抗变化的随机性和重燃时间间隔的随机性开展间歇性重燃电弧模型的研究。黑盒电弧模型中,Cassie-Mayr联合模型能完整的描述电弧电流从大电流到小电流的变化过程,但存在从大电流变化为小电流的判据模糊,转换过程突变的问题。为此,论文通过引入连续过渡函数解决上述问题。同时,为描述弧道电阻的变化特性,利用Fermi函数对联合模型中Mayr模型和Cassie模型进行权重分配。以改进的Cassie-Mayr单次燃弧模型为基础,根据工频熄弧理论,通过设置燃弧时间长短表征间歇性重燃的随机性,从而建立了间歇性重燃电弧模型。利用该模型,对典型10kV配电网单辐射型网架结构的接地故障进行模拟仿真,采用快速傅里叶变换(fast Fourier transform,FFT)和小波包分析提取了不同条件下故障电压、电流、高次谐波、零序分量以及频率分布等故障特征。研究结果表明:改进后Cassie-Mayr联合模型不但解决了电弧电流从大电流到小电流的转换突变问题,且不同模型权重占比的分配更能准确地表征实际燃弧弧道阻抗变化的随机性;通过设置电弧燃弧时间长短,准确地描述间歇性重燃的随机性;电弧断续时刻为非整数周期下的过电压、过电流幅值高于整数周期;电缆线路增大了故障线路电流,过电流可达3.81~7.20pu,不利于熄弧;大电流系统故障相零序电流主频在0~400Hz,小电流系统故障相零序电流主频在1200~1600Hz。The intermittent reignition of electric arcs is the most typical characteristic of single-phase grounding faults in distribution networks.The existing electric arc models often overlook this intermittent reignition characteristic,resulting in the inaccurately description of the characteristics of discontinuous arc glow grounding faults,thus affecting the relay protection operations.To address this,the paper proposes a method for establishing an intermittent reignition electric arc model and analyzes the characteristics of discontinuous arc glow grounding faults based on this model.The random variation of arc impedance serves as an important indicator of intermittent reignitions,so the study focuses on the stochastic nature of arc impedance variations and the reignition time intervals in the intermittent reignition electric arc model.In the black box electric arc model,the Cassie-Mayr combined model accurately describes the transition of arc current from high to low values.However,there exist an issue of fuzzy criteria for transitioning from high to low currents and the abrupt changes during the transition process.To address these issues,the paper introduces a continuous transition function and utilizes the Fermi function to assign weights to the Mayr and Cassie models in the combined model to represent the changing chara-cteristics of arc resistance.Building upon the improved Cassie-Mayr single reignition arc model,the intermittent reignition electric arc model is established by incorporating the stochastic nature of intermittent reignition through the duration of arc reignition,as defined by the power-frequency arc extinguishing theory.Using this model,simulation and analysis of a typical 10 kV distribution network with single-radiation grid structure are conducted.The fault characteristics such as fault voltage,fault current,higher harmonics,zero-sequence components,and frequency distribution are extracted using the Fast Fourier Transform(FFT)and the wavelet packet analysis under different conditions.The resear

关 键 词：配电网 单相接地故障 间歇性重燃电弧模型 中性点接地 小波包分析 

分 类 号：TM721[电气工程—电力系统及自动化]