基于超级电容的变速风电机组参与系统频率优化策略

Frequency optimization strategy of variable speed wind turbine participation system based on ultracapacitor

面对系统功率波动导致频率变化时,不同风速下风机为系统提供惯性支撑和参与系统一次调频的能力不同.在低风速下,系统频率下降时,双馈风机提供频率响应后,电力系统频率有二次跌落的风险;当风速过高时,风机转子转速难以提升,而桨距角调频速度慢、精度低.基于此,提出了基于超级电容的变速风电机组参与系统频率优化策略.在双馈风力发电机直流母线处接入超级电容模块,考虑了不同风速下风机参与系统调频的特性,优化虚拟惯性系数和储能控制系数.解决了风机在临界转子转速下难以参与系统调频的问题,且在不同风速下参与系统调频时能进行最优功率出力,提高了风电机组参与系统一次调频的能力.最后,通过仿真实验验证了所提控制策略的有效性.

In the face of frequency change caused by system power fluctuation,the ability of wind turbine to provide inertial support for the system and participate in the primary frequency regulation of the system is different under different wind speeds.Under low wind speed,when the system frequency drops,the power system frequency has the risk of secondary drop after the doubly fed wind turbine provides frequency response;When the wind speed is too high,the rotor speed of wind turbine is difficult to improve,and the pitch angle frequency modulation speed is slow and the accuracy is low.Based on this,the frequency optimization strategy of variable speed wind turbine participation system based on ultracapacitor is proposed.The super capacitor module is connected to the DC bus of doubly fed wind turbine generator.Considering the characteristics of wind turbine participating in system frequency modulation under different wind speeds,the virtual inertia coefficient and energy storage control coefficient are optimized.The problem that it is difficult for the wind turbine to participate in the system frequency modulation at the critical rotor speed is solved,and the optimal power output can be carried out when participating in the system frequency modulation at different wind speeds,which improves the ability of the wind turbine to participate in the system primary frequency modulation.Finally,the effectiveness of the proposed control strategy is verified by simulation experiments.