直驱永磁风力发电机绕组短路保护研究

发布时间：2018-01-20 01:35

本文关键词： 直驱永磁发电机绕组短路计算 ANSOFT暂态仿真主保护配置　出处：《新疆大学》2017年硕士论文　论文类型：学位论文

【摘要】：随着风力发电机组装机容量的增大和投产运营数量的增多,风电产业得到了迅速发展,风电在中国的能源中占比越来越大。最近时期以来,因风力发电机内部小故障,导致大面积机组被切除,最终造成电网电压跌落,引起严重事故。风力发电机绕组短路是机组内部典型的故障之一,电机的绕组短路故障能够产生危害性极大的电流,这将间接或直接地给电网带来巨大的经济损失,因此十分有必要对风力发电机内部绕组配置主保护。风电机组内部绕组保护研究可以提高风力发电场的运行效率,降低风电机组故障的发生,有效地提高机组运行的安全性,甚至对能源结构的调整以及风电产业的发展都具有十分重大的作用。首先,论文概述了直驱永磁同步风力发电机的绕组结构以及三相静止坐标系下永磁发电机的数学模型,建立了直驱永磁风力发电机空载有限元模型。在此模型基础上用外电路模拟匝间及单相接地短路,基于ANSOFT MAXWELL暂态仿真得到故障前后绕组电流的波形并分析其特征,根据定子绕组短路电流的大小,找出其故障规律。其次,分析了永磁发电机不同匝数绕组短路故障,以1.5MW直驱永磁风力发电机绕组为研究对象,利用ANSOFT MEXWELL仿真得出短路电流有效值,得出当定子发生匝间短路时,定子各相电流呈不对称分布,且随着故障程度的加深,故障相电流的增幅及幅值明显大于非故障相。第三,对发电机绕组单相接地短路故障进行了仿真,对比分析得出故障前后电流变化趋势,深入研究绕组的短路特征,得出绕组发生单相接地短路故障时,各相短路电流对发电机绕组的威胁更加严重。最后,针对直驱永磁风力大电机组绕组发生绕组匝间及单相接地故障,配置了“一纵两横”的绕组短路保护,从而改变了直驱永磁风力发电机组无保护的现状。通过内部绕组不同故障程度的数据对比分析,对于匝间短路故障,各相横向短路电流差明显大于纵向短路电流差,横差保护的灵敏度优于不完全纵差保护的灵敏度。
[Abstract]:With the increase of installed capacity and operational quantity of wind turbine, wind power industry has developed rapidly, and wind power accounts for more and more energy in China. Because of the small fault inside the wind turbine, the large area unit is excised, and finally the voltage of the power network falls, which causes the serious accident. The wind turbine winding short circuit is one of the typical faults inside the unit. The winding short circuit fault of the motor can produce great harmful current, which will bring huge economic loss to the power network indirectly or directly. Therefore, it is necessary to configure the main protection for the windings of the wind turbine. The research on the protection of the inner windings of the wind turbine can improve the operational efficiency of the wind farm and reduce the occurrence of the fault of the wind turbine. Effectively improve the safety of unit operation, even the adjustment of energy structure and the development of wind power industry have a very important role. First of all. The winding structure of direct-drive permanent magnet synchronous wind generator and the mathematical model of permanent magnet generator in three-phase static coordinate system are summarized in this paper. The no-load finite element model of direct-drive permanent magnet wind turbine is established, and the inter-turn and single-phase earthing short circuit is simulated by external circuit on the basis of the model. Based on the transient simulation of ANSOFT MAXWELL, the waveform of winding current before and after the fault is obtained and its characteristics are analyzed. According to the size of short-circuit current of stator winding, the fault law is found out. Secondly. The short-circuit fault of different turns winding of permanent magnet generator is analyzed. Taking the winding of 1.5MW direct-drive permanent magnet wind generator as the research object, the effective value of short-circuit current is obtained by ANSOFT MEXWELL simulation. It is concluded that when inter-turn short circuit occurs in the stator, the stator phase currents show asymmetric distribution, and with the deepening of the fault degree, the increase and amplitude of the fault phase current is obviously larger than that of the non-fault phase. Third. The single-phase earthing short-circuit fault of generator windings is simulated, and the trend of current change before and after fault is obtained, and the short-circuit characteristics of windings are deeply studied, and the single-phase earthing short-circuit fault of windings is obtained. The short-circuit current of each phase is more serious to the generator winding. Finally, in view of the winding inter-turn and single-phase grounding fault of the direct drive permanent magnet wind motor group windings, the "one longitudinal and two horizontal" winding short circuit protection is provided. Thus, the situation of direct-drive permanent magnet wind turbine without protection is changed. By comparing and analyzing the data of different fault degree of internal windings, the inter-turn short-circuit fault is analyzed. The transverse short-circuit current difference of each phase is obviously larger than that of longitudinal short-circuit current, and the sensitivity of transverse differential protection is better than that of incomplete longitudinal differential protection.
【学位授予单位】：新疆大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM315

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