基于冲击电压下电缆等效电阻值的绝缘状态评估新方法

为了评估电力电缆的绝缘状态,提出了冲击电压下电缆等效电阻值的计算和绝缘状态评估的新方法。将电力电缆简化为RC串并联等效电路,并分别模拟电力电缆各层及整体的电路参数。利用电磁场理论给出了电力电缆的等效电路参数的数学表达式,提出了冲击电压下计算电力电缆等效电阻值的方法,并理论推导出了冲击电压下电力电缆等效电阻的计算表达式,从而总结出了一种评估电缆绝缘状态的新方法。利用电力系统暂态仿真软件(Alternative Transients Program,ATP)和矩阵实验室(Matrix Laboratory,MATLAB)软件进行了电缆电阻的仿真和计算;仿真与计算结果表明,仿真设置的电阻值与理论计算的等效电阻值之间误差最大为0.4%,验证了电缆绝缘状态评估新方法的可靠性。

A new method of insulation condition assessment based on equivalent resistance value of cable under impulse voltage

In order to evaluate the insulation condition of power cable,a new method to calculate equivalent resistance value and evaluate insulation condition of cable was presented under the impulse voltage.To simulate the circuit parameters of the components and the whole layer of power cable independently,the RC series and parallel equivalent circuit of power cable was built.The mathematical expression of the equivalent circuit parameters of the power cable was given by using the electromagnetic field theory,and the method to calculate the equivalent resistance of power cable was proposed,and the calculation expression of the equivalent resistance of power cable under impulse voltage was derived,and a new method for evaluating the insulation condition of power cable was summarized.The equivalent resistance of cable was simulated and calculated by ATP (alternative transients program) and MATLAB (matrix laboratory) software.The simulation and calculation results show that the maximum error between the setting value of resistance and the calculating value of the equivalent resistance is 0.4％,and the reliability of the new method is verified.