Two-Stage Research on AC/DC Hybrid High-Voltage Distribution Network Based on Network Reconfiguration and SOP Coordinated Control

Abstract

DC power grid has the advantages of large power supply capacity, easy access to clean energy, low loss, and easy power control. With the increasing penetration rate of distributed generation and DC load in low-voltage transmission network, the traditional radial AC distribution form develops into AC-DC hybrid form. Large-scale distributed energy access is an important feature of future distribution system. Aiming at the AC-DC hybrid distribution system with soft tie-in switch and voltage source converter, considering the network congestion caused by large-scale access of distributed energy, a two-stage congestion management mechanism is proposed. This strategy solves the congestion problem of AC/DC hybrid transmission network with the help of the power flow control ability of AC/DC transmission network’s own optimization control means and congestion management services provided by distributed energy sources. According to the experiment, the total distributed generation power of DC link is 15 MW, and the load power is 10 MW, that is, the remaining power of DC link is 5 MW, the total distributed generation power of AC link is 8 MW, and the load power is 15 MW, that is, the power shortage of AC link is 7 MW. In the first stage, the tie-in switch, SOP and VSC are coordinated and optimized, and in the second stage, the flexible adjustment ability provided by distributed energy makes up for the deficiency of the adjustment ability of direct control means in some periods of severe congestion and meets the requirements of congestion management of AC-DC hybrid transmission network under high-permeability distributed generation.