基于CVT的特高压换流站复杂电磁环境下操作过电压测量

特高压换流站内设备开关操作时很容易产生操作过电压，但由于电压等级高、换流站内存在强电磁干扰等因素目前仍缺少对这些过电压进行测量的有效手段。为此对电容式电压互感器（CVT）改装，进行操作过电压测量研究，通过建立CVT串联分压模型以及仿真电磁单元对过电压测量的影响，论证改装测量过电压的可行性。通过优化传感器内部结构，降低杂散参数，以提高传感器抗干扰能力。通过对测量系统外屏蔽、信号电缆匹配、屏蔽和接地等措施的优化，实现换流站强电磁干扰下过电压信号的有效采集。在±800 kV陕北换流站进行现场测试，有效采集了投切空载线路和低压电抗器时的操作过电压。搭建了一种特高压换流站操作过电压测量系统并通过现场测试验证了设计方案的有效性和安全性。

CVT-Based Switching Overvoltage Measurement of UHV Converter Station under Complex Electromagnetic Environment

UHV converter station is prone to produce switching overvoltage during switching operation, However, due to its high voltage level, strong electromagnetic interference and other factors, there is still no effective means to measure the overvoltage. Therefore, a study is carried out on the switching overvoltage measurement by refitting the capacitive voltage transformer (CVT). By establishing a CVT series voltage division model, the influence of electromagnetic unit on the overvoltage measurement is simulated, and the feasibility of refitting is demonstrated. The internal structure of sensors is optimized to reduce stray parameters, consequently improve the anti-interference ability of the sensors. The outer shielding, signal cable matching, shielding and grounding of the measurement system are optimized to effectively collect the overvoltage signals under strong electromagnetic interference. A field test was carried out in the ±800 kV UHV Shaanbei Converter Station, and the switching overvoltage during switching the no-load line and the low-voltage reactor was effectively recorded. In a word, an overvoltage measurement system is developed for the UHV converter station, and the effectiveness and safety of the design scheme is verified through field tests. This work is supported by Science & Technology Project of State Grid Shaanxi Electric Power Research Institute (Research on Overvoltage Test Technology in Complex Electromagnetic Environment of ±800 kV Converter Station-Sensor and Electromagnetic shielding Design Optimization Research, No.SGTYHT/19-JS-217).