A highly reliable AC/DC hybrid distribution network with active-links

AC/DC hybrid distribution network (AC/DC-HDN) will become mainstream in the evolution of distribution networks. This paper proposes a highly reliable AC/DC-HDN with active-links. An active-link is such a kind of link circuit that can rapidly and automatically switch the healthy power supply to users under fault conditions. Three types of active-links are proposed in this paper: AAD active-link composed of a three-winding link transformer and a bi-directional link AC/DC converter and linked two 10 kV AC lines and a lower voltage DC line; DDD active-link composed of three backstop-diodes and used to connect a load branch to two DC lines and an energy storage system (ESS); MDC active-link included of four sets of isolating switches and diodes and connected four DC line in any-mode. Based on the proposed active-links, a highly reliable AC/DC-HDN including four T-shaped sub-networks is designed and a corresponding multi-agent based three-layer optimal control strategy with the objective of maximizing the consumption of renewable energy is proposed. Simulations demonstrate the reliability of the proposed AC/DC-HDN and the effectiveness of the strategy.