计及网侧变流器的双馈感应发电机稳态短路电流实用计算方法研究

Research on Practical Calculation Method of Steady⁃state Short Circuit Current of Doubly Fed Induction Generator Considering Grid Side Converter

双馈感应发电机组(DFIG)的大规模并网使得电网的故障特征发生变化,进而影响了继电保护装置的动作特性评估,故研究DFIG的低电压穿越(LVRT)特性有重要意义。然而目前的研究尚未全面考虑最新风机并网要求、实际LVRT控制策略以及网侧变流器(GSC)3大因素对DFIG稳态短路电流的影响。基于主流厂家DFIG的LVRT控制策略以及我国最新风机并网要求,分别建立了LVRT期间定子和GSC的稳态模型,提出了DFIG稳态短路电流的实用计算方法。并进一步在RTLAB上搭建了含DFIG实际控制器的半实物仿真平台,验证了实用计算方法对于短路电流有效值的计算误差小于3%,短路电流相角的计算误差小于2.5%。本文的研究成果对DFIG接入系统的继电保护整定等方向有重要意义。

The large-scale grid-connection of doubly fed induction generator(DFIG)has changed the fault characteristics of the power grid,and then affected the operation characteristic assessment of the relay protection devices.Therefore,it is very important to study the lower voltage ride through(LVRT)characteristics of DFIG.However,the current researches haven’t fully considered the influences of the latest wind turbine grid-connection requirements,the actual LVRT control strategy and the grid-side converter(GSC)on the steady-state short-circuit current of DFIG.In this paper,the steady-state models of stator and GSC during LVRT period is set up respectively on the basis of the LVRT strategy of DFIG of mainstream factories and the latest wind turbine grid-connection requirements in China,and a practical calculation method for the steady-state short-circuit current of DFIG is proposed.Furthermore,a semi-physical simulation platform including actual controller of DFIG is set up on RTLAB further.It is verified that the calculation error of the effective value of short-circuit current by the practical calculation method is less than 3%,and the calculation error of the short-circuit current phase angle is less than 2.5%.The research results in this paper are of great significance to the relay protection setting of DFIG access system.