考虑频率稳定约束的新能源电力系统临界惯量计算方法

New energy power system critical inertia estimation method considering frequency stability constraints

针对新能源并网的弱惯量、零惯量特征对电力系统频率稳定的影响,提出一种计及频率稳定约束的新能源电力系统临界惯量的估算方法。首先,建立系统频率动态响应数学模型,求解惯量中心频率时域表达式。然后,基于频率响应模型求解并分析系统惯量与相关频率稳定性指标的关系,进而计及频率变化率和频率最大偏差约束估算系统临界惯量理论值和计算值。最后,基于临界惯量提出一项电力系统频率稳定性指标,来评估功率扰动后的电力系统频率稳定性,并结合电力系统实际运行惯量得出新能源虚拟惯量参考值。在DIgSILENT PowerFactory中以改进的IEEE 10机39节点新英格兰系统和某区域电网仿真算例对所提计算方法进行仿真验证。

Given the influence of the weak inertia and zero inertia characteristics of grid-connected new energy on power system frequency stability,a new energy power system critical inertia estimation method that takes into account frequency stability constraints is proposed.First,this paper establishes a mathematical model of the system frequency dynamic response,and solves the time-domain expression of the inertia center frequency.Then,based on the frequency response model,the relationship between the system inertia and the related frequency stability index is established and analyzed,and then the frequency change rate and the frequency maximum deviation constraints are considered in order to estimate the theoretical and calculated values of the system critical inertia.Finally,based on the critical inertia,a power system frequency stability index is proposed to evaluate that stability after a power disturbance,and is combined with the actual operating inertia of the power system to obtain a reference value of the new energy virtual inertia.In DIgSILENT PowerFactory,an improved IEEE 10-machine 39-node New England system and a regional power grid simulation example are used to simulate and verify the proposed calculation method.