摘要
本文针对具有低电压穿越功能的经过逆变器并网的电源,首先分析其交流侧故障后的暂态特性与传统旋转电动机暂态特性的不同,指出不同主要体现在两方面,其一为前者短路电流中不含有暂态直流分量,其二为若忽略逆变器限流的快速动态,短路前后逆变器相当于稳态电流突变的电流源,因此基于短路前后电源状态量不突变的传统的短路电流计算方法不能用于含逆变器电源电网的短路电流计算。本文对传统方法进行了改进,用传统方法和改进方法分别编程实现了含逆变器电源的某配网的短路电流计算,通过对计算结果的对比分析,指出了传统方法存在的问题,和改进方法的适用范围及超范围应用时的误差。
The transient characteristics of inverter interfaced energy with low voltage ride-through（LVRT） after the occurrence of power grid faults is firstly analyzed and compared with those of traditional rotating machine. It is presented that there are two major differences between these two kinds of generators, one of which is there is no DC component in the case of inverter interfaced and the other is the inverter can be assumed as current source with a sudden steady state current change when subject to grid fault, given the quick inverter＇s current limiting dynamic neglected. Thus the traditional short circuit current calculation method which is based on the fact that the state variables of generators keep unchanged, cannot be applied to the grid with inverter interfaced generators because of the sudden change in steady state current of inverter. Then an improved method suitable for both the rotating machine generators and invert interfaced generators is proposed and programmed to calculate the short circuit current of power system. Lastly, the calculation results under various conditions are compared to prove the previous analysis and show the short circuit patterns for different kinds of generators and different calculation methods.
出处
《电气技术》
2015年第9期38-42,共5页
Electrical Engineering
基金
国家高技术研究发展计划(863计划)(2011AA05A106)
