电网短路时双馈感应发电机转子电流的分析与计算  

Analysis and Calculation of Rotor Currents for Doubly-fed Induction Generators Under Short Circuits in Power Grids

作　　者：熊小伏[1] 欧阳金鑫[1] 

机构地区：[1]输配电装备及系统安全与新技术国家重点实验室(重庆大学),重庆市沙坪坝区400030

出　　处：《中国电机工程学报》2012年第28期114-121,11,共8页Proceedings of the CSEE

基　　金：重庆大学输配电国家重点实验室资助重点项目(2007DA10512711102);重庆大学输配电国家重点实验室资助项目(2007DA10512709202);中央高校基本科研业务费资助(CDJXS11150026)~~

摘　　要：双馈风电机组对机端电压跌落比较敏感,随着风电装机容量的不断增加,电网故障时双馈风电机组转子电流的准确分析与评估变得十分重要,关系着双馈风电机组低电压穿越的实现以及故障电气量的分析与计算。从电网短路时双馈感应发电机的暂态过程出发,分析了双馈感应发电机定子动态过程以及变流器调控对转子电流的影响,采用空间矢量法和坐标变换方法推导了电网对称短路和不对称短路时转子电流的表达式,通过时域仿真和算例结果验证了表达式的正确性。所提出的表达式利用机端电压以及变流器控制参数即可计算得到电网短路时任意时刻的转子电流,具有清晰的物理意义以及较好的实用性。Doubly-fed induction generators （DFIG） are very sensitive to the disturbances of grid, so dynamic characteristics of its rotor current become very important under the rapid increase of DFIG-based wind generation. The implementations of low voltage ride through and short-circuit calculation of electric quantities depend on the accurate assessment of rotor current. In this paper, the transient processes of DFIG under grid fault were analyzed. The influences caused by stator dynamic process and output of converter on rotor current were studied. The expressions of the rotor current under symmetric or asymmetric faults were deduced by the coordinate transform methods. The effectiveness of the expression was proved by simulation and calculation results. The rotor current during a grid fault can be calculated by using terminal voltages and the control parameters of converter, so the proposed expressions have clear physical meaning and good practicability.

关 键 词：电网 短路电流 风力发电 故障分析 低电压穿 越 双馈感应发电机 

分 类 号：TM[电气工程]