Abstract:
In recent years, frequent extreme disasters have caused huge losses to the distribution network, so it is extremely important to improve the resilience of the distribution network. With the large increase of DC sources and loads such as distributed photovoltaic, energy storage and electric vehicles, the form of urban distribution network is transforming from AC distribution network to AC/DC hybrid distribution network. DC lines have the advantage of flexible interconnection, which can break the bottleneck in the radial operation of AC distribution networks and achieve flexible networking after disasters, thus effectively improving the resilience of distribution networks. Aiming at the urban AC/DC hybrid distribution network with photovoltaicstorage-charging integrated station(PSCIS), a power supply recovery strategy that fully considers the characteristics of flexible DC interconnection and regulation ability is proposed. First, considering the distribution of critical loads and local resources after disasters, a topology generation method for emergency power supply recovery with DC lines as the core is proposed. Secondly,based on the AC/DC recovery topology, a two-stage resilience improvement optimization model for the distribution network is established. In the first stage, the load recovery sequence is optimized with the objective of maximizing the power supply of critical loads. In the second stage, the emergency power supply output of the PSCIS is optimized with the objective of minimizing the network loss. The simulation results show that the proposed strategy can make full use of the DC flexible interconnection capability and power support capability of PSCIS to restore critical loads, and the two-stage fault recovery method has good feasibility and adaptability.