Optimal Siting, Sizing and Outputting of Multiple SAPFs Under Intelligent Nonlinear Loads Partitioning for System-Level Harmonic Mitigation

With the massive and distributed access of nonlinear loads to distribution networks, traditional point-to-point harmonic compensation method becomes inefficient. Meanwhile, the demand for system-level harmonic control by few shunt active power filters (SAPFs) has emerged, which lays emphasis on the optimal allocation and coordination of SAPFs, in terms of location, capacity, and output. Existing allocation algorithms suffer from local minimum, characterized by excessive locations and unreasonable capacity assignment of SAPFs. Therefore, this article introduces a new nonlinear loads partition model and a cluster-based SAPFs allocation algorithm. First, the existing basic SAPFs allocation model is reviewed for problem description. By reconstructing the existing model, a three-level nonlinear loads partition model is built, in which the essence of system-level harmonic control is revealed and the harmonic compensation distance between SAPF and the nonlinear load is defined. Based on this distance, a modified K-means clustering algorithm is implemented to partition nonlinear loads and obtain the optimal allocation of SAPFs. Finally, the IEEE 18-bus standard system and its simplified eight-bus network are designed, respectively, in simulation and experiment. Results verify that the proposed SAPFs allocation method has the advantages of less location, less total capacity, and good harmonic suppression performance.