短路电流直流分量实用计算方法研究

短路电流直流分量含量对断路器开断能力有很大影响,然而对直流分量的计算至今缺乏简单实用的方法。分析短路电流直流分量产生原理及其衰减特性,结合电力网络数学模型的特点,提出了基于转移阻抗理论的短路电流直流分量实用计算方法:将电力系统复杂网络近似简化为以短路点为中心的辐射形网络,求出各发电机所提供短路电流直流分量及其衰减情况,最终对所有分支短路电流直流分量求和近似计算出故障点短路电流直流分量。通过实用计算方案与EMTP仿真计算以及故障录波的对比分析,验证了该方法的准确性。

Research on Practical Calculation Method of DC Component of Short Circuit Current

DC component of short circuit current has a great influence on the breaking capacity of the circuit breaker. However, its calculation is still lack of a simple and practical method. Based on the analysis of the principle and attenuation characteristics of the DC component of short circuit current and the characteristics of the mathematical model of power network, a practical method for calculating the DC component of short circuit current is proposed. The complex network of power system is simplified into a radial network with short circuit point as the center, and then the DC component of each generator branch is calculated, finally, the DC component of short circuit current at fault point is approximately calculated by summing the DC component of all branch short circuit currents. The accuracy of the method is verified by the comparison between practical calculation and EMTP simulation.