基于零序电流-电压微分特性的小电阻接地系统单相接地故障保护原理  

Grounding faults protection in low-resistance grounded systems based on zero-sequence current-voltage differential characteristics

作　　者：彭刚 钟振鑫 肖瑞超 李海锋[3] Peng Gang;Zhong Zhenxin;Xiao Ruichao;Li Haifeng(Meizhou Power Supply Bureau,Guangdong Power Grid Co.,Ltd.,Meizhou 514021,Guangdong,China;Huizhou Power Supply Bureau,Guangdong Power Grid Co.,Ltd.,Huizhou 516199,Guangdong,China;South China University of Technology,Guangzhou 510640,China)

机构地区：[1]广东电网有限责任公司梅州供电局,广东梅州514021 [2]广东电网有限责任公司惠州供电局,广东惠州516199 [3]华南理工大学,广州510640

出　　处：《电测与仪表》2021年第7期143-149,共7页Electrical Measurement & Instrumentation

基　　金：广东电网有限责任公司科技项目资助(031300KK52170067)。

摘　　要：中性点经小电阻接地的系统适用于电缆居多的配电网,然而由于配网馈线所处环境复杂,造成了现有的基于零序电流阶段式的保护方案无法满足单相高阻接地故障快速、灵敏地检测需求。针对此现象,文中通过分析故障线路和非故障线路零序电流-零序电压的关系,寻求两者不同的故障特征,由此提出一种基于线路零序电流与母线零序电压微分值波形相似度的保护算法。所提保护算法通过对线路的零序电流和零序电压进行采样,并根据线路零序电流与母线零序电压微分值的波形相似度来判断线路是否发生单相接地故障,可大大提高单相高阻接地故障保护的灵敏度。通过PSCAD仿真测试验证了该算法的有效性。The neutral point through the low-resistance grounding system is applicable to the distribution network with majority of cables.However,due to the complicated environment of the distribution feeder,single-phase high-impedance ground faults cannot be detected rapidly and sensitively by existing zero-sequence overcurrent protection.Aiming at this problem,this paper analyzes the relationship between the zero-sequence current and the zero-sequence voltage of faulty line and healthy line,and seeks different fault characteristics between them.A protection algorithm based on the waveform similarity between the line zero-sequence current and the bus zero-sequence voltage differential is proposed in this paper.The proposed protection algorithm samples the zero-sequence current and the zero-sequence voltage of the line,and judges whether a single-phase ground fault occurs on the line by comparing the waveform similarity between the line zero-sequence current and the bus zero-sequence voltage differential value,which can greatly improve the sensitivity of single-phase high-impedance grounding fault protection.Finally,the effectiveness of the proposed algorithm is verified by PSCAD simulation.

关 键 词：小电阻接地系统 高阻接地故障 零序保护 波形相似度 PSCAD 

分 类 号：TM933[电气工程—电力电子与电力传动]