特高压交流开关型可控避雷器电位分布研究

Study on Potential Distribution of UHV AC Switch Type Controllable Metal Oxide Arrester

特高压交流开关型可控避雷器可以通过闭合控制单元开关,短接底部单元节,进而起到抑制操作过电压的作用。当此类避雷器处于正常工作状态时,由于控制单元开关断口电容等杂散电容的影响,其电位分布比普通氧化锌避雷器更加复杂。为获取特高压交流开关型可控避雷器的电位分布,基于有限元法在Ansoft Maxwell环境下对其电压分布进行仿真研究。将仿真结果与已有试验数据进行对比分析,验证了模型准确性,并在此基础上分别研究了在承受稳态电压、操作过电压及雷电过电压时特高压交流开关型可控避雷器整体电压分布趋势及最大电压分布不均匀系数所在位置。研究结果为监控避雷器状态和优化避雷器结构工作提供了依据。

The valve piece of the bottom unit section of UHV AC switch type controllable metal oxide arrester(CMOA)can be shortened by closing the control unit switch,which can then suppress switching surges.When CMOA is at normal working state,its potential distribution is affected by stray capacitance such as the capacitance between break fractures.Therefore,the potential distribution of CMOA is more complicated than that of conventional metal oxide arrester(MOA).To establish a more accurate understanding of the potential distribution of CMOA,Ansoft Maxwell was used to simulate the voltage distribution based on a finite element method.The accuracy of the model was verified by comparing the simulation results with the existing experimental data.The holistic voltage distribution trend of the CMOA and the position of the maximum voltage distribution unevenness coefficient were studied respectively under the steady voltage,operating overvoltage and lightning overvoltage.The present study has laid basis for monitoring the state and optimizing the structure of the arrester.