观馈风电系统低电压穿越技术研究

发布时间：2018-02-08 21:58

本文关键词： 风力发电双馈感应式电机低电压穿越定子Crowbar电路超级电容器储能系统　出处：《南京师范大学》2016年硕士论文　论文类型：学位论文

【摘要】：随着风力发电技术的长足发展,风电机组装机容量与接入电网的规模与日俱增,电网电压跌落引起大规模风电机组脱网运行严重威胁到电力系统的稳定性。为了满足风电场接入电力系统的规定,采取有效的低电压故障保护措施,保持风电系统与电网的不间断运行并向电网提供必要的无功功率以支持电网恢复己刻不容缓。相比直驱永磁风力发电机组与恒速风力发电机组的低电压穿越技术研究而言,双馈风力发电系统对电网故障尤其敏感。因此,本文主要针对双馈风电系统的低电压穿越技术展开研究,主要内容如下：1.根据双馈感应式风电系统的机械、电气及物理特性,对双馈感应式风力发电系统进行模块化建模,从而得到适用于低电压运行研究的动态模型。确定了基于恒电压控制的转子侧变流器SPWM控制策略和基于电网电压矢量控制的网侧变流器SPWM控制策略,且对该动态模型进行仿真验证。2.根据电路的基本定律对电网故障下双馈电机的电磁暂态特性进行理论分析,重点分析了故障发生瞬间DFIG定子磁链和转子电流以及直流母线电压的变化特性。利用PSCAD/EMTDC软件对三相对称短路时DFIG暂态特性进行仿真分析。3.提出了基于DFIG定子Crowbar电路及超级电容器储能系统的协调保护措施,并且利用双馈风电系统自身的无功功率调节能力,向电网提供无功功率补偿。利用PSCAD/EMTDC仿真平台,在电网发生故障时,对所提出的保护措施进行仿真分析。仿真结果表明该方案能够有效抑制电网故障时引起的过电压和过电流,提高DFIG的低电压运行的能力。4.提出了在DFIG并网点串联电阻器的主动式低电压保护措施。利用PSCAD/EMTDC进行仿真分析,仿真结果表明并网点串联电阻器能够有效的实现DFIG低电压穿越而无需增加其他硬件保护措施。
[Abstract]:With the rapid development of wind power generation technology, the installed capacity of wind turbines and the scale of connecting to the power grid are increasing day by day. The de-grid operation of large-scale wind turbine caused by voltage drop in power grid seriously threatens the stability of power system. In order to meet the requirements of wind farm connecting to power system, effective low-voltage fault protection measures are taken. It is urgent to maintain the uninterrupted operation of the wind power system and the power grid and provide the necessary reactive power to support the restoration of the grid. Compared with the low-voltage traversing technology of the direct-drive permanent magnet wind turbine and the constant speed wind turbine, it is urgent to do so. The doubly-fed wind power system is especially sensitive to power grid faults. Therefore, this paper mainly focuses on the low-voltage traversing technology of the doubly-fed wind power system, the main contents are as follows: 1. According to the mechanical, electrical and physical characteristics of the doubly-fed induction wind power system, The modular modeling of doubly-fed induction wind power generation system is carried out. The SPWM control strategy of rotor side converter based on constant voltage control and the SPWM control strategy of grid side converter based on grid voltage vector control are determined. The dynamic model is verified by simulation. 2. According to the basic laws of circuit, the electromagnetic transient characteristics of doubly-fed machine under power network fault are analyzed theoretically. The variation characteristics of stator flux, rotor current and DC bus voltage of DFIG at the moment of fault occurrence are analyzed emphatically. The transient characteristics of DFIG under three phase symmetric short circuit are simulated by PSCAD/EMTDC software. 3. Based on DFIG stator Crowbar current, the DFIG transient characteristics are simulated and analyzed. 3. Coordinated protection measures for road and supercapacitor energy storage systems, The reactive power compensation is provided to the power network by using the reactive power regulation ability of the doubly-fed wind power system, and the PSCAD/EMTDC simulation platform is used when the power network fails. The simulation results show that the proposed scheme can effectively suppress the overvoltage and overcurrent caused by the fault of the power network. To improve the ability of low voltage operation of DFIG. 4. The active low voltage protection measures in DFIG parallel dot series resistor are put forward. The simulation analysis is carried out by using PSCAD/EMTDC. The simulation results show that the parallel dot series resistor can effectively realize DFIG low voltage traversing without adding other hardware protection measures.
【学位授予单位】：南京师范大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TM614

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