空间电荷条件下超、特高压直流复合绝缘子电压分布

Potential Distribution of EHV and UHV Direct Current Composite Insulator Considering the Effect of Space Charge

针对高压直流输电线绝缘子沿串电压分布问题,提出按离子流场模型求解。采用有限元迭代方法,求解了离子流场控制方程。对±500 kV直流复合绝缘子沿串电场及电压分布进行了计算,并与不考虑空间电荷条件下的静电场求解结果进行了对比,通过与试验测量结果比较,验证了考虑空间电荷时,计算结果更接近实际测量结果,并将该方法应用于特高压±800 kV直流绝缘子沿串电压分布问题的计算求解中。结果表明,由于电晕产生电荷的抑制作用,绝缘子在高压端及低压端的电压和电场强度均有较大改变。得到了不能将直流绝缘子沿串电压分布问题简化为无电荷影响的模型求解的结论,建议采用离子流场有限元迭代计算方法求解该问题。

The voltage distribution along the DC composite insulator string was focused on ,and the solution of ion flow field problem was put forward. By using the results achieved in the solving method of DC ionized field, voltage and electric field strength distribution along the DC composite insulator was calculated. The result was compared with that solved in electrostatic field without considering the space charge. The result was better than the measured by the method without space charge condition. Then the method was used to solve voltage distribution along the ±800 kV UHV DC composite insulator string. It is revealed that the voltage and eleetric field strength distort a lot near high voltage end and low voltage end of the insulator because of the inhibited effect of the charge produced by corona. It is concluded that the space charge cannot be omitted in analyzing the voltage and electric field along DC insulator, and FEM iterative computation of DC ionized field is advised.