基于运算电感分析电网对称故障下双馈型风力发电机Crowbar保护动作期间的定子电流特征  

Characteristics Analysis to DFIG-based Wind Turbine’s Stator Current During Crowbar Protection and Symmetrical Fault by Operational Inductance

作　　者：常远瞩 胡家兵[1] 田旭 张祥成 孔祥平 袁宇波 CHANG Yuanzhu;HU Jiabing;TIAN Xu;ZHANG Xiangcheng;KONG Xiangping;YUAN Yubo(State Key Laboratory of Advanced Electromagnetic Engineering and Technology(School of Electrical and Electronic Engineering,Huazhong University of Science and Technology),Wuhan 430074,Hubei Province,China;State Grid Qinghai Electric Power Company,Xining 810000,Qinghai Province,China;State Grid Jiangsu Electric Power Co.Ltd.,Research Institute,Nanjing 211103,Jiangsu Province,China)

机构地区：[1]强电磁工程与新技术国家重点实验室(华中科技大学电气与电子工程学院),湖北省武汉市430074 [2]国网青海省电力公司,青海省西宁市810000 [3]国网江苏省电力有限公司电力科学研究院,江苏省南京市211103

出　　处：《中国电机工程学报》2019年第21期6192-6199,共8页Proceedings of the CSEE

基　　金：国家重点研发计划项目(2016YFB0900100);国家电网公司科技项目(52283015000M);青海省基础研究计划项目(2016-ZJ-767)~~

摘　　要：双馈型风力发电机具备经济的变速恒频发电能力,已成为现代电力系统的重要电源。与传统同步发电机不同,当电网发生短路故障后,受限于全控励磁变换器的控制能力,双馈型风力发电机需依赖附加电路与控制完成并网导则中的各种故障穿越要求,这直接导致了双馈电机具有不同于传统同步发电机的复杂故障电流特征。该文利用运算电感推导了电网对称故障及Crowbar保护动作这一典型情景下双馈电机定子电流的解析表达式,并分析了定子电流成分的频率、初始幅值、衰减时间常数及频率偏移特征。相较于已有结果,考虑了双馈型风力发电机故障前的初始运行状态,提出的解析表达式具有简洁易用的特点。此外,基于所提出的解析表达式,对比了其与无阻尼隐极同步发电机故障电流特征的异同,能够帮助读者从同步机电源电流特征的角度直观地认识双馈型风力发电机的故障电流特征。最后,通过与商用双馈型风力发电机电磁仿真模型的对比证明了所提出解析表达式具备优良的准确性。分析结果能为高风电渗透率电力系统的装备选型与继电保护设计等提供解析依据。As a preferred choice for the variable-speed wind turbine(WT), DFIG based WT has become a typical power source in modern power systems of China. However, once a short circuit occurs in power gird, Crowbar protection circuit is typically employed to ride through grid fault by protecting its non-full-size power converters, which is different from the traditional power source(synchronous generator). As a result, the fault characteristic of DFIG based WT during Crowbar protection is distinct and should be analyzed thoroughly. An analytical expression was proposed by using the concept of operational inductance to present characteristics of DFIG based WT’s stator current components, including initial magnitudes, decay time constants, frequency and frequency deviation. Compared with the existing literatures, the initial states of DFIG were considered and the proposed analytical expression is much simpler to use and understand. With the comparison to fault current of a cylindrical-rotor synchronous generator without any damper winding, readers are expected to understand the characteristics better from a perspective of traditional power source. The accuracy of this analysis is validated by EMTP simulation of a commercial DFIG based WT. The results of this paper can be used for rating powerequipment and setting protection relays of power systems with high penetrated DFIG based WTs.

关 键 词：解析表达式 双馈发电机 故障电流 运算电感 故障穿越 

分 类 号：TM614[电气工程—电力系统及自动化]