基于恒频注入信号计算配电网分布电容的方案与应用

Fixed-Frequency Signal Injection Based Schemes to Calculate Grounding Distributed Capacitance of Distribution Network and Applications

基于恒频信号注入技术的基本原理并结合实际应用,提出了从消弧线圈副边、从母线电压互感器二次绕组和从并联电容器组中性点注入恒频电流信号的3种实现方案,对3种方案的工作原理进行了详细分析,并推导了基于恒频注入信号计算配电网等效对地分布电容的表达式。从实际应用的角度讨论了注入信号的检测方法,设计了具体的滤波实现方案。实验室仿真与现场测试结果表明所提方法能够较准确地计算出配电网的等效对地分布电容,验证了恒频信号注入方案实现的可行性。

Based on the basic principle of fixed-frequency signal injection and combining with its practical application, three kinds of schemes are proposed to inject fixed-frequency signal at the secondary side of arc suppression coil（ASC）, at secondary winding of bus-bar potential transformer and at the neutral of shunt capacitor bank. The working principles of the three proposed injection schemes are analyzed in detail and the fixed-frequency signal injection based expression to calculate equivalent grounding distributed capacitance of distribution network is derived. From the viewpoint of actual application the detection of the injected signal is discussed, and filtering implementation scheme is designed. Results of lab simulation and field measurement show that using the proposed method the equivalent grounding distributed capacitance of distribution network can be calculated accurately, thus the feasibility of implementing fixed-frequency signal injection schemes is validated.