配电变压器雷击建模及雷电防护

配电变压器(简称配变)作为配网的重要组成部分,绝缘水平低,易遭受雷电过电压的侵害,其安全运行对配电网稳定性及可靠性具有十分重要的意义。采用散射参数测量法,测量配变散射参数并经数据处理获得配变的阻抗幅频特性,经电路拟合构建了适用于雷击情况的配变宽频模型,并经基于模拟退火法的粒子群算法对等效电路参数进行优化,实测结果表明配变实际输出响应与文中宽频模型仿真结果吻合度较高。基于该宽频模型分析了冲击电晕对配变过电压传播的影响以及配变防雷保护措施,结果表明冲击电晕显著减小配变过电压幅值,配变低压侧加装避雷器对其防雷作用明显。

Lightning Stroke Modeling and Lightning Protection of Distribution Transformers

As an important part of distribution network, distribution transformer(DT)has low insulation level and is vulnerable to lightning overvoltage. The safe operation of distribution transformer is very important to the stability and reliability of distribution network. In this paper, the scattering parameter measurement method is used to establish distribution transformer model, amplitude frequency characteristics is obtained by impedance measurement and data processing of distribution transformer circuit fitting and particle swarm optimization algorithm based on simulated annealing is intriduced to optimize the model. The measured results show that the measurement results of the distribution transformer under lightning stroke are in good agreement with the simulation results established in this paper. Based on the broadband model, the influence of shock corona on voltage distribution of distribution transformer and the lightning protection measures of distribution transformer are analyzed.The results show that the shock corona significantly reduces the amplitude of the transformer over voltage,and the lightning protection effect of lightning arrester installed on the low voltage side of the transformer substation is obvious.