双馈风电场短路电流特性对距离保护的影响及保护策略研究

目前双馈风机短路电流特性对风电场送出线距离保护的影响以及相关的研究,一般是在计及Crowbar保护动作后的基础上进行的,少有考虑到计及转子侧变流器(RSC)控制后的DFIG短路电流特性对距离保护的影响。基于此,分析了计及Crowbar保护动作后和计及RSC控制两种运行工况下双馈风机的短路电流特性之间的差异。在此基础上,解析推导了计及Crowbar保护动作时的转速频率分量、计及RSC控制时的暂态自然分量对全周傅里叶算法产生的计算偏差表达式。进而分析双馈风电场提供的短路电流对传统距离保护的影响,并提出了故障后适用于两种运行工况下的时域距离保护。最后在Matlab/Simulink平台上搭建并网双馈风机电磁暂态仿真模型。仿真分析了计及Crowbar保护动作和计及RSC控制两种情况下,传统距离保护和时域距离保护的动作特性。

Study on the influence of short-circuit current characteristics of a doubly-fed wind farm on distance protection and protection strategy

At present, studies on the influence of short-circuit current characteristics of a doubly fed induction generator on distance protection of wind farm feeder lines and related research are generally carried out on the basis of taking Crowbar protection action into account. There is little literature considering the influence of short-circuit current characteristics of DFIG on distance protection under the control of Rotor-Side Converter (RSC). Thus this paper analyses the difference of short-circuit current characteristics of doubly fed induction generator considering Crowbar protection operation and RSC control operation. The expressions of calculation deviation of the speed-frequency component and transient natural component for full-cycle Fourier algorithm considering Crowbar protection operation and RSC control are deduced and analyzed. The purpose is to analyze the influence of short-circuit current from doubly-fed wind farm on traditional distance protection. Also a time-domain distance protection method adapted to two operating conditions after fault is proposed. Finally, the electromagnetic transient simulation model of grid-connected doubly fed induction generator is built on the platform of Matlab/Simulink. The operational characteristics of traditional distance protection and time-domain distance protection are simulated and analyzed considering Crowbar protection action and RSC control. This work is supported by National Natural Science Foundation of China (No. 51367009).