基于量测数据的风电场等效虚拟惯量评估方法

Evaluation of Equivalent Virtual Inertia of Wind Farm Based on Measured Data

研究风电场等效虚拟惯量评估方法可以定量掌握风电场对电网的惯量贡献。已有方法通过建立含有虚拟惯量控制的风电机组简化模型并结合转子运动方程推导出风电场等效惯量的计算公式,但该方法却存在所需参数众多且不易获得的问题。对此,提出一种从易于获得的量测数据中求取风电场等效惯量的方法。首先,介绍了风电虚拟惯量的概念。其次,对风电机组惯量响应过程中自身动能和输出电能的转换进行分析,并根据能量守恒原理提出一种利用风电场公共耦合点(point of common coupling,PCC)有功-频率量测数据进行计算的惯量评估方法,该方法可以避免基于系统辨识方法在评估过程中对辨识模型降阶所带来的误差,从而得到更高精度的惯量评估结果。最后,在PSASP中建立仿真算例验证了所提方法的有效性和优越性。

The study of the equivalent virtual inertia evaluation of a wind farm may quantitatively realize the inertia contribution of a wind farm to power grid.The existing methods deduce the calculation formula of the equivalent inertia of the wind farm by establishing the simplified model of the wind turbine with virtual inertia control and combining with the rotor motion equation.However,these methods have the problem that there are many parameters needed but it is difficult to obtain them.Therefore,this paper proposes a method to obtain the equivalent inertia of a wind farm from the available measured data.Firstly,the concept of the wind power virtual inertia is introduced.Secondly,the conversion of the self-kinetic energy and the output electric energy in the inertia response process of the wind turbine is analyzed.A new method of the inertia evaluation is proposed based on the active power-frequency measurement data of the PCC point of the wind farm according to the principle of energy conservation.This method is able to avoid the errors caused by the order reduction of the identification model in the evaluation process based on the system identification so as to obtain more accurate inertia evaluation.Finally,a simulation example is established in the PSASP to verify the effectiveness and superiority of the proposed method.