低电压穿越过程中DFIG型风电场同步稳定及无功电流控制方法

发布时间：2018-04-17 18:26

本文选题：风电场 + 严重故障穿越　；参考：《中国电机工程学报》2017年15期

【摘要】：电网故障持续过程中,低电压穿越导则要求风电场输出规定的无功电流以支撑电网电压恢复。目前电网运营商通常规定风电场配置一定容量的静态无功补偿装置(static synchronous compensator,STATCOM)来提供无功支撑,该文对配有STATCOM的风电场进行研究。为满足低压穿越要求,风电机组和STATCOM都需采用基于锁相环的电流矢量控制方法。但是在电网严重故障时,由于锁相环与风电场电流控制之间存在动态交互,风电场输出与电网存在同步失稳的风险。该文以双馈型发电机的(doubly fed induction generator,DFIG)风电场为例,分析了风电场的同步稳定机理和条件,得出实现风电场的同步稳定必须输出一定的有功电流。而STATCOM只能输出无功,因此需DFIG的协助才能实现同步稳定;同时受功率变流器输出能力的限制,DFIG无功输出能力减弱,需STATCOM协助才能满足并网导则的无功需求。基于此,提出一种DFIG和STATCOM的协同电流控制方法,根据电网传输线路阻抗角协调控制风电场输出电流的有功、无功分量,确保风电场同步于电网运行。最后通过仿真验证了理论分析和控制方法的有效性。
[Abstract]:Low voltage traversing guidelines require wind farms to output specified reactive currents to support grid voltage recovery in the process of power grid failure.At present, grid operators usually require wind farms to be equipped with static synchronous compensator STATCOMs with certain capacity to provide reactive power support. In this paper, a wind farm with STATCOM is studied.In order to meet the requirement of low voltage crossing, both wind turbine and STATCOM need to adopt current vector control method based on phase locked loop (PLL).However, when the power network is in serious trouble, there is a risk of synchronous instability between the wind farm output and the power grid due to the dynamic interaction between the PLL and the current control of the wind farm.Taking doubly fed induction generator wind farm of doubly-fed generator as an example, this paper analyzes the synchronous stabilization mechanism and conditions of wind farm, and concludes that certain active current must be output to realize synchronous stabilization of wind farm.But STATCOM can only output reactive power, so it needs the assistance of DFIG to realize synchronization stability, and the reactive power output ability of STATCOM is weakened due to the limitation of output ability of power converter, so it needs STATCOM assistance to meet the reactive power demand of grid connection guidelines.Based on this, a cooperative current control method based on DFIG and STATCOM is proposed. According to the impedance angle of transmission line, the active and reactive power components of wind farm output current are coordinated to ensure the wind farm to run synchronously in the power grid.Finally, the effectiveness of the theoretical analysis and control method is verified by simulation.
【作者单位】：武汉理工大学自动化学院;清华大学自动化系;龙源(北京)风电工程技术有限公司;
【基金】：国家重点研发计划(2016YFB0900302) 国家自然科学基金项目(U1510208)~~
【分类号】：TM614

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