A Unified DC-AC Power Flow Algorithm of Distribution Network with Distributed Generation

Abstract

Abstract. With the development of rectification technology and DC equipment, hybrid DC-AC transmission has arisen in the distribution network. In addition, the penetration of distributed generation (DG) in the distribution network makes the analysis of power system more complicated. As a key measure of grid programming and operating, a practical power flow method of DC-AC distribution network is urgent to study. Firstly, the mathematical model of DGs is given in this paper, and the analysis of the operation and control mode of DC-AC distribution system with voltage source converter (VSC) is conducted. Then a calculation method of hybrid DC-AC distribution system with DGs is proposed, in which constant-power DG, voltage controlled DG and DG with voltage static characteristic is concerned. An improved forward backward sweep method is given, concerning VSC, AC circuits, DC circuits and various type of DGs, which achieves the purpose of unified DC-AC power flow calculation. Finally, case study for a 90-node distribution network with DG integration is conducted to demonstrate the effectiveness of the method.