零序电流互感器配大电阻的配电网单相接地故障检测

Single-phase grounding fault detection based on zero-sequence current transformer with large resistance

为了简化配电网单相接地故障检测装置的构成和增强单相接地故障特征,探索了一种基于零序电流互感器配较大负载电阻的配电网单相接地故障检测方法。分析了零序电流互感器配大负载电阻时的特性,并通过仿真和实验手段验证了其正确性。在此基础上,研究了二次侧电阻的参数选取问题,探讨了所研究方法在中性点不接地配电网用户侧分界开关单相接地保护装置和变电站单相接地选线装置中的应用,结合典型例子采用数字仿真的方法验证了其可行性,并与传统方法对比分析,结果表明所论述方法在进行单相接地选线时具有故障特征更明显的特点,在实现用户侧单相接地保护时可使电路更简单。

To simplify the circuit and increase the fault signature for single-phase grounding faults detection device in distribution networks,a single-phase grounding fault detection method based on zero-sequence current transformer with large resistance is proposed.The characteristics of zero-sequence current transformers with large secondary resistance are investigated,and its correctness is verified by simulation and experiment results.On this basis,the parameter selection of the secondary side resistance is studied.The applications of the proposed methods in relay protection of the customer circuit breaker and the single-phase grounding line selection in substations are described with typical examples,the feasibility of which is verified by the digital simulation method.Compared with the traditional approaches,the results show that the proposed method makes the detection circuit simpler and increases the fault signature for single-phase grounding protection on the user side.