基于动态电压调节器的风电机组低电压穿越策略
Low Voltage Ride Through Strategy for Wind Turbine Systems Using Dynamic Voltage Restorers
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摘要: 随着并网大型风电场装机容量的逐年增长,低电压穿越(LVRT)能力已经逐渐成为风电机组并网的一个重要指标。文中提出了一种利用动态电压调节器(DVR)辅助风电机组在电网电压跌落工况下实现LVRT的策略。DVR串联接入风电机组机端和电网公共连接点(PCC)之间,电网电压正常时通过静态开关柜将其旁路,电网电压跌落时利用反压技术进行快速投切,DVR通过调节使风电机组机端电压维持正常;同时,DVR在风电机组和电网之间提供功率通道,利用直流母线上的刹车电阻消耗掉过剩功率,保证直流电容电压的稳定及风电机组的正常运行。利用恒速异步风力发电机(FSIG)配合DVR建立了仿真模型和实验平台,给出了在PSCAD/EMTDC环境下的仿真及实验结果。Abstract: With the penetration level of large-scale grid-connected wind farms increasing year by year,low voltage ride through(LVRT) capability is required by many countries for power quality and fail-safe operation of grid faults.A new dynamic strategy using dynamic voltage restorer(DVR) is proposed to improve LVRT capability of wind turbine generators(WTGs).During the voltage dip,DVR will be connected in series between grid and the generator by opening the static switch cabinet.And the power balance between grid and generator is achieved by using the dynamic braking resistor of DVR.In order to increase the response speed of DVR,anti-voltage technology is used to make the thyristor control rectifier in static switch cabinet shutting off immediately.PSCAD/EMTDC simulations and experiments are carried out to prove the effectiveness of the proposed technique.