旋转备用下双馈风电机组初值算法

Initialization Method of DFIG-based Wind Power Units with Spinning Reserve

风电机组运行参数计算是风电系统稳态调度和暂态分析的基础。恒kopt模型常用于最大功率点跟踪方式下双馈感应发电机(DFIG)初值计算,但是其所得发电机转速与风力机最优转速相矛盾,且不适用于旋转备用方式。文中针对DFIG旋转备用下的初值问题,提出了转速约束和出力约束2种算法。前者取转速固定,但不要求是最优转速,风力机捕捉机械功率已知,待求转子和变流器电压、风电机组有功出力,需要与电网潮流联立求解;后者取风电机组功率已知,待求转子和变流器电压、转速(或桨距角)及风力机出力,与电网潮流独立求解。2种算法的有效约束和待求变量数不同,但得到的风力机和发电机转速相符,均适用于风速低于或高于额定风速情况下的旋转备用运行。算例结果验证了所提模型的可行性和正确性。

The initial values of wind power units are the basis of steady-state dispatch and transient analysis for wind power systems.Constant kopt model is often applied for initialization of doubly-fed induction generators（DFIGs） in the maximum power point tracking strategy.However,the resultant speeds of the induction generator and the wind turbine are contradictory,and this model is unsuitable for spinning reserve.For initial values of DFIGs with spinning reserve,two initialization methods,i.e.speed constraint and power constraint,are proposed.The former method sets the rotor speed constant（not necessarily the optimal speed）,with the known captured power,the active output of wind power unit and the voltages of the rotor and the converters are solved simultaneously with network power flow equations.The latter sets the power output as known variable,the voltages of the rotor and the converters,the slip（or the pitch angle） and the captured power are solved independently with network power flow equations.Both methods have different numbers of constraints and variables,but yield consistent rotor speed and are suitable for spinning reserve dispatch regardless of wind speed.The example results validate the feasibility and accuracy of the proposed methods.