PDF《短路电流直流分量实用计算方法研究》

短路电流直流分量实用计算方法研究 张旭航1 , 黄阮明1 , 曹炜2 , 余婕1 , 仇成1 , 周明2 (1.

国网上海市电力公司经济技术研究院, 上海 200001;

2. 上海电力学院电气工程学院, 上海 200090) 摘要: 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. 关键词: 短路电流;

直流分量;

衰减特性;

转移阻抗;

实用计算方法 Research on Practical Calculation Method of DC Component of Short Circuit Current ZHANG Xuhang1 , HUANG Ruanming1 , CAO Wei2 , YU Jie1 , QIU Cheng1 , ZHOU Ming2 (1. State Grid Shanghai Electric Power Economic &

Technological Institute, Shanghai 200001, China;

2. School of Electrical Engineering, Shanghai University of Electric Power, Shanghai 200090, China) Abstract: DC component of short circuit current has a great influence on the breaking capacity of the circuit break? er. 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 accura? cy of the method is verified by the comparison between practical calculation and EMTP simulation. Key words: short circuit current;

DC component;

attenuation characteristic;

transfer impedance;

practical calcu? lation method

0 引言 随着经济的快速发展, 全社会的用电负荷持续 攀升, 电力系统的装机容量逐年扩大;

且随着特高 压工程的逐步发展、 新型能源的不断接入和电网联 系的进一步加强[1-4] , 负荷中心地区的短路电流水平 将会进一步增长.而为降低输电损耗, 电力变压器 和输电线构成的输电网中电抗电阻比也越来越大, 导致系统短路电流中的直流分量衰减越来越慢, 为限 制短路电流使用的串联电抗使得问题更加严重[5-7] . 短路电流直流分量衰减变慢, 将增大短路冲击 电流、 短路全电流以及断路器需要开断电流的直流 分量含量等[8-9] , 对电网中某些断流容量裕度很小的 断路器是否能按配置要求及时开断短路电流是严 峻的考验[10] , 给系统安全运行埋下了隐患. 然而, 对直流分量衰减的计算一直缺乏工程上 简单实用的方法和工具.GB 15544―2013[11] 《三相 交流系统短路电流计算标准》 提出用等效频率法, 第55卷第5期: 0169-0174 2019年5月16日High Voltage Apparatus Vol.55, No.5: 0169-0174 May 16,