考虑风电减载调频的高比例风电电力系统优化调度方法

Optimal Dispatching Method of High-proportion Wind Power Systems Considering Wind Power Reserve for Frequency Adjustment

受制于同步发电机组调频容量和调频速度的限制,风速波动使得高比例风电系统的频率稳定问题日趋严峻。变速风电机组(variable speed wind turbine,VSWT)通过提前减载参与电网调频是解决风电随机性影响的有效方法。VSWT的减载率是影响电力系统安全性和经济性的关键,但受电网调频容量、需求以及风速、机组安全约束等的影响,目前尚难以从系统层面确定恰当的风电减载率,使得风电减载运行的效果有限,甚至引发一系列安全问题。为此,提出了基于VSWT动态减载的电力系统调频思想,充分考虑风电功率预测误差、VSWT减载控制约束、同步发电机组调频容量和系统运行经济性的影响,提出了考虑风电减载调频的高比例风电系统优化调度方法。研究了风电功率预测误差对电网频率的影响;推导了VSWT在减载控制约束下的最大可减载率及最大正、负调频容量;提出了基于风电动态减载的电网新型调度模式;基于机会约束规划,建立了考虑风电减载调频的高比例风电系统优化模型;最后,通过算例验证了所提方法的有效性。

Limited by the reserve capacity and speed of the synchronous generators,the frequency reliability of wind power systems with high-proportion wind energy caused by wind speed fluctuations is becoming increasingly severe.Wind power reserve of variable speed wind turbines(VSWTs)is effective to solve the random impacts of wind power.The rate of power reserve of VSWT is the key to the safety and economy of power grids.However,it is difficult to determine the suitable value at the system level due to the influences of reserve capacity,the demand,and the safety constraints of wind speed and VSWTs,which restrains the effects of wind power reserve and even causes a series of safety problems.To this end,an idea of power system frequency adjustment based on dynamic VSWT power reserve is proposed.By fully considering the effects of wind power prediction errors(WPPEs),the VSWT constraints,the reserve capacity of synchronous generators,and the system economy,a dispatching method with wind power reserve for frequency adjustment is proposed in this paper.The effects of the WPPE on frequency is studied.The maximum rate of power reserve,and the maximum positive and negative reserve capacity of the VSWT are derived.A new grid scheduling mode based on dynamic wind power reserve is proposed.Based on the chance-constrained programming,an optimal model considering wind power reserve for frequency adjustment is established.Finally,the validity of the proposed method is verified by simulation studies.