应用阻抗变换技术的变电站接地网检测系统激励源的设计与应用

针对变电站接地网接地性能检测和缺陷诊断的需要，设计了专用的异频正弦波激励源系统。基于线性放大和阻抗变换技术，在较宽的频带内和较大输出电流的情况下，实现了频率和输出电流的连续调节，解决了功率放大器和接地网负载之间的阻抗匹配问题。实验结果表明激励源系统的频率特性、带负载能力和输出电流能力符合设计要求。通过测量地表磁感应强度和电位分布，诊断接地网导体断点的现场应用表明激励源的设计合理，能够满足变电站接地网缺陷诊断和接地性能检测等工程实际的需要。

Design and Application of Exciting Power for Substation Grounding Grids Testing System Based on Impedance Transformation Technology

A special sine-wave exciting source with different frequency for testing the functions of substation grounding grids and diagnosing faults is designed. Based on technologies of linear amplifying and impedance transformation, the problem of impedance matching between the power amplifier and the load of grounding grid is solved in the conditions of wider frequency band and heavier output current. At the same time, the working frequency and output current can be adjusted continuously. Experimental results show that the frequency characteristics and the abilities of driving load and current output can satisfy the design requirements. The mesh conductor broken faults of grounding grids are diagnosed by measuring the surface magnetic induction intensities and the potential distributions. The practical applications show that the design of the source is reasonable and functioning.