摘要
为解决随着电源容量增加和电网网架的增强,使运行中的断路器开断能力裕度越来越低的问题,提出考虑动态负荷计算衰减的短路电流以校核断路器的开断能力的方法。本文首先采用旋转电机统一模型将单机系统短路电流周期分量衰减代数式转化为发电机、感应电动机(由动态负荷等效)电势衰减的代数式。其次,借鉴机电暂态计算中的坐标变换使单机下代数表达的衰减的旋转电机电势经坐标变换后与电网方程联立。最后,线性代数求解联立方程得到多机系统中衰减的短路电流周期分量,避免了像机电暂态仿真那样求解微分方程。结果与机电暂态仿真所得短路电流周期分量相比,误差很小。
The increase in power supply capacity and the enhancement of power grid has made the breaking capacity margin of a circuit breaker under operation become even lower.To solve this problem,a method of calculating the decaying short-circuit current considering dynamic load is proposed in this paper to check the breaking capacity of the circuit breaker.First,a unified rotating machine model is adopted to transform the algebraic formula for the attenuation of the short-circuit current’s periodic component of the single-machine system into that for the electric potential attenuation of the generator and induction motor(equivalent to dynamic load).Then,based on the coordinate transformation in the calculation of electromechanical transient state,the algebraic formula for the rotating machine’s electric potential attenuation is combined with the grid equation after coordinate transformation.Finally,by means of linear algebra,the simultaneous equations are solved to obtain the attenuated short-circuit current’s periodic component in the multi-machine system,which avoids solving differential equations like electromechanical transient simulations.The results are compared with the short-circuit current’s periodic component obtained by the electromechanical transient simulation,indicating that the corresponding error is very small.
作者
黄阮明
曹炜
张铭
郭明星
何必伦
HUANG Ruanming;CAO Wei;ZHANG Ming;GUO Mingxing;HE Bilun(Economic&Technological Institute,State Grid Shanghai Municipal Electric Power Company,Shanghai 200233,China;College of Electrical Engineering,Shanghai University of Electric Power,Shanghai 200090,China)
出处
《电力系统及其自动化学报》
CSCD
北大核心
2021年第10期105-111,共7页
Proceedings of the CSU-EPSA
关键词
短路电流
衰减
坐标变换
动态负荷
short-circuit current
attenuation
coordinate transformation
dynamic load
