故障限流装置中MOV能量吸收及热特性研究

金属氧化物限压器(metal oxide voltage limiter, MOV)作为串联谐振型故障限流器的关键部件,其可靠运行尤为重要。以110kV单相线路为例,利用电磁暂态分析程序对MOV在系统短路故障过程中能量吸收的特性进行仿真分析。仿真结果表明,短路故障时间越长,MOV需要吸收的能量越多;快速开关闭合时间的长短决定了MOV短时吸收能量的大小。进一步利用有限元计算方法,以MOV单元阀片和MOV本体结构为研究对象,对暂态过程中MOV的热特性进行研究,得出了MOV阀片温升与短路故障时间及注入能量之间的变化曲线,同时计算出MOV单元阀片及MOV本体的温度场分布,分析了其温度分布特性。在此基础上,制作了实际MOV本体模型,并进行了MOV温升的实验测定,结果表明实验测量与相应的理论计算符合较好,证明了相应计算方法的可靠性。研究结果为设计故障限流装置保护配置策略及MOV温升保护策略提供了工程参考,为MOV的本体设计提供了理论依据。

Research on energy absorption and thermal characteristics of MOV in fault current limiter

As a key part of series resonant type fault current limiter, the reliable operation of metal oxide voltage limiter(MOV)is especially important. By using electromagnetic transient analysis program, a 110 kV single-phase circuit was taken as the example for analyzing the energy absorption characteristics of MOV for the system short-circuit fault. The results showed that the longer short-circuit faults time, the more energy that the MOV absorbed and that the closed time of fast switch could determines the energy that MOV absorbed. In addition, the ANSYS finite element analysis program was also used for analyzing the transient thermal characteristics of MOV, by taking MOV valve units and the whole MOV as the research object. The temperature rise of MOV valve units as a function of the time of short-circuit fault and the injected energy was obtained. At the same time, the temperature field distribution of MOV valve units and the whole MOV were worked out, the temperature distribution characteristics were also analyzed. Based on the above analyses, a practical MOV was constructed and its temperature increase was experimentally determined. Good agreement between the determined temperature increase and the corresponding theoretical calculations was obtained, which indicating the calculations reliability. The research results could provided theoretical direction for the design of configuration strategy for fault current limiters and for the protection strategy of MOV temperature rise, and could present theoretical reference for the design of MOV.