考虑频率约束的新能源电网极限渗透率估计方法

Estimation of Extreme Penetration Rate of New Energy Grid Considering Frequency Constraints

大规模新能源的并网导致系统惯量下降以及一次调频能力不足,面对功率扰动下的系统频率问题逐渐凸显,为合理规划未来新能源接入比例,亟需计算在频率约束条件下的新能源渗透率极限。根据风力发电机组所处风速区间的不同,在传统单机频率响应模型的基础上,基于小信号分析法推导低、中、高风速区间内风力机频率变化与附加功率的传递函数关系,建立一种多风速区间影响的含高渗透新能源接入的频率响应模型,并由此模型提出在频率约束条件下的新能源并网极限渗透率计算方法。在修改的IEEE 14节点系统仿真结果中验证所提评估方法的准确性及控制参数对频率响应的影响。

With the decrease of system inertia due to the grid connection of large-scale new energy and the insufficiency of primary frequency modulation capability,the system frequency problem under the face of power perturbation has gradually come to the forefront.In order to rationally plan for the proportion of new energy access in the future,it is urgent to calculate the limit of the new energy penetration rate under the frequency constraints.According to the different wind speed intervals where wind turbines are located,based on the traditional single-machine system frequency response model,the transfer function relationship between wind turbine frequency change and additional power in the low,medium and high wind speed intervals is derived based on small-signal analysis,and a frequency response model with high penetration of new energy access is established with the influence of multiple wind speed intervals,and the new energy grid-connected limit of new energy penetration under the frequency constraints is proposed from this model.The frequency response model with high penetration of new energy access is established,and the calculation method of new energy grid-connected limit under frequency constraint is proposed.The accuracy of the proposed evaluation method and the influence of control parameters on the frequency response are verified in the simulation results of the modified IEEE 14 node system.