Holomorphic Embedding Power Flow Algorithm for Isolated AC Microgrids With Hierarchical Control
Ying Huang, Xiaomeng Ai, Jiakun Fang, Shichang Cui, Runfeng Zhong, Wei Yao, Jinyu Wen
Abstract
Power flow (PF) calculation plays a fundamental role in the steady-state analysis of isolated microgrids (MGs). In this paper, a novel analytical PF algorithm based on holomorphic embedding (HE) is proposed for isolated AC MGs considering hierarchical control (HC). With a deliberate design in embedding technique, the presented algorithm not only inherits the deterministic property of the canonical embedding that enables to derive the upper-branch (operable) solution explicitly, but also is compatible with the HC characteristic of isolated MGs. Furthermore, the embedded PF model features a general structure with a constant recursive matrix, which can accommodate various bus types and network re-configurations (including both radial and meshed networks), as well as non-nonlinearities of voltage-dependent load models. Case studies are carried out on 3 test systems: a 12-bus MG and modified IEEE 33-bus and 123-bus distribution systems. Numerical results reveal the applicability and efficacy of the proposed algorithm.