工频试验变压器高压绕组高电位电流测量系统研制与应用

目前对工频试验变压器的常规测量均为稳态工频参数，未涉及试验变压器高压绕组高电位电流的暂态状况。研制了一套基于Rogowski电流传感器和光电传输技术的高电位电流测量系统，可测量最大冲击电流峰值1 000 A，最大工频电流有效值6 A、频率范围50 Hz~20 MHz；进行了频率响应试验、工频小电流和冲击大电流的性能试验，实测了绝缘子工频闪络时和GIS隔离开关开合感性小电流试验时流经试验变压器高压绕组的电流波形。通过试验数据分析了高陡度暂态电流对变压器的绝缘损伤和测量的意义，探讨了通过比较测得的暂态电流最大陡度以衡量试验变压器保护措施有效性的方法。该系统可为衡量试验变压器保护措施的有效性、改进试验回路以及试验变压器损伤、故障等相关的研究提供参考数据，避免盲目使用造成试验变压器绝缘损伤，对保障其安全运行和科研研究具有重要意义。

Development and Application of Measurement System for High Potential Current in High Voltage Winding of Power Frequency Test Transformer

At present，there is steady-state power frequency parameter in the conventional measurement of power frequency test transformer，not involving the transient state of high potential current of high voltage winding for the test transformer. To this end, the paper develops a high potential current measurement system based on Rogowski current sensor and photoelectric transmission technology, measuring the impulse current below the peak value of 1 000 A， power frequency current below the maximum of 6 A and frequency range from 50 Hz to 20 MHz. The system is tested with frequency response， small power frequency current and high impulse current，and is used to measure the current waveforms flowing through the test transformer high voltage winding during the frequency voltage flashover test of insulator and the inductive current switching test of GIS disconnector. Based on test data， both the insulation damage of the transformer caused by high steep transient current and the significance of this measurement is analyzed. The method of judging the effectiveness of the protective measures for the test transformers is discussed by comparing the maximum steepness of transient current measured. The system can provide reference data for evaluating the effectiveness of the transformer protection measures， improving the test circuit and the researches related to the test transformer damage and fault， and it is important to avoid the insulation damage of the test transformer caused by blind use and to ensure its safe operation and scientific research.