超高压V型绝缘子串含零值绝缘子的空间电场畸变特性研究

Spatial Electric Field Distortion Characteristics of EHV V Type Insulator String with Zero Value Insulator

作为500 kV超高压输电线路重要组成部分的V型绝缘子串长期运行后其绝缘性能下降,易产生零值绝缘子;非接触零值绝缘子的检测需要准确的含零值绝缘子电场特性作为理论依据。因此,本研究建立了500 kV超高压V型绝缘子串含零值绝缘子空间电场仿真计算模型,研究了不同电场监测路径下的电场监测波形特征及畸变特性。研究结果表明:高压端、中部、低压端零值绝缘子的存在均会使电场波形发生较为明显的畸变。对于合成电场和电场纵向分量,当存在零值绝缘子时,零值绝缘子附近将会出现向下畸变的波峰(电场值的突降);对于电场横向分量,则反之。含零值绝缘子时的电场幅值畸变量与幅值畸变比随着零值绝缘子位置的改变而变化。从计算结果可以看出,电场幅幅值畸变比最小值可达18.11%,表明从电场的畸变特性入手可实现超高压V型绝缘子串零值绝缘子的定位。最后,非接触式现场检测实验表明,本研究仿真结果与真实电场波形情况高度一致,本研究所提出的基于电场畸变特性的方法可以有效的识别零值绝缘子位置。

As an important part of 500 kV EHV transmission line,the insulation performance of V-shaped insulator string decreases after long-term operation,and it is easy to produce zero value insulator;The detection of non-contact zero value insulators requires accurate electric field characteristics of zero value insulators as a theoretical basis.Therefore,this paper establishes the space electric field simulation calculation model of 500 kV EHV V insulator string with zero value insulator,and studies the electric field monitoring waveform characteristics and distortion characteristics under different electric field monitoring paths.The results show that the existence of zero value insulators at high voltage end,middle end and low voltage end will obviously distort the electric field waveform.For the composite electric field and the longitudinal component of the electric field,when there is a zero insulator,there will be a downward distorted peak near the zero insulator(sudden drop of the electric field value);For the transverse component of the electric field,the opposite is true.The electric field amplitude distortion and amplitude distortion ratio with zero insulator change with the change of zero insulator position.It can be seen from the calculation results that the minimum amplitude distortion ratio of electric field can reach 18.11%,indicating that the zero value insulator positioning of EHV V insulator string can be realized from the distortion characteristics of electric field.Finally,the non-contact field detection experiment shows that the simulation results are highly consistent with the real electric field waveform.The method based on the electric field distortion characteristics proposed in this paper can effectively identify the position of zero value insulator.