适用于短路故障分析的风电场动态等值建模方法

DYNAMIC EQUIVALENT MODEL OF WIND FARM FOR SHORT-CIRCUIT FAULTS ANALYSIS

针对风电场集电网络等值较为粗略、对非对称故障时等值模型精确度关注较少的情况,提出一种适用于短路故障分析的风电场动态等值建模方法。首先,依据系统潮流计算结果对集电网络进行等值解耦计算,并采用基于模块度的K均值算法对各风力机端电压进行聚类分析,实现风电机群内的多机聚合。其次,考虑到集电网络分布电容的影响,对聚合后风电场设置集中无功补偿电容。随后,为保证非对称故障过程中等值模型的有效性,提出风电场零序网络的等值方法。最后,基于时域仿真软件PSCAD/EMTDC下搭建的电磁暂态仿真模型,验证了所提动态等值方法的有效性。

In order to study the dynamic characteristics of interactions between the large-scale wind farms and grid,dynamic equivalent modeling methods for wind farms has attracted extensive attention.Aiming at the existing problems that the equivalence of the wind farm collection network is relatively rough and the accuracy of equivalent models is often ignored during asymmetric faults,a dynamic equivalent modeling method,which is suitable for short-circuit fault analysis for wind farm,is proposed in the paper.Firstly,the decoupling of the collector network is carried out according to the power flow calculation results.Secondly,the modularity based K-means algorithm is adopted for clustering the wind turbine system output ac voltages to realize the optimal multi-machine aggregation.Considering the influence of distributed capacitance of the collector network,the centralized reactive compensation capacitor is set for the wind farm after aggregation.Then,in order to ensure the validity of the equivalent model during asymmetric faults,the equivalent method of zero-sequence network is proposed.Finally,the electromagnetic transient model built in the time-domain simulation software PSCAD/EMTDC verifies the effectiveness of the proposed method.