Research On Power Supply Restoration Strategy In Smart Distribution Network

The distribution network is an important part of power grid,and the pursuit of high reliability in distribution network has always been a critical focus which makes research in power restoration important.On the one hand,facing the access and use of new technologies such as distributed generation,energy storage,demand response on the distribution network in the secondary system of control,the power supply restoration shall keep updating to catch up with the renew on the smart distribution network and to take “smart” distribution network elements into account while taking full advantage of.On the other hand,with the development and breakthrough of power electronics technology,more controllable power electronic devices are installed in the distribution network.How to make better use of these controllable devices to improve the system reliability and restoration result after fault is also a very significant research direction in the field of power supply restoration.This article studies the power supply restoration of the smart distribution network from two different aspects.Firstly,it focuses on the upgrade of the power restoration algorithm in the secondary system of the smart distribution network.In this part this paper proposes a fast power restoration strategy based on network equivalence and parallelization for smart distribution network which contains “smart” elements such as distributed generation,spare capacity and energy storage equipment.This heuristic power restoration optimization algorithm can comprehensively consider all kinds of support factors in the distribution network with “flexible sources” according to the specific power loss situation,and provide a fast,reliable,cost-effective and reasonable power supply restoration plan.The second part focuses on “soft open point”(SOP),a new type of power electronic device of primary equipment in smart distribution network that replaces tie switch and can control transmitted active power and reactive power separately.Based on the principle of control mode and the concept of equivalent source,this paper establishes a joint optimization model of soft open point and equivalent source,and adopts the primal-dual interior point method(a fast,robust optimization solver)to solve the power restoration problem containing SOP.Examples are given to verify the feasibility of the joint optimization model and the effectiveness of the optimization algorithm.The advantages of SOP over tie switches in power supply restoration is demonstrated.The different allocation of SOP in the distribution network leading to discrepant restoration results are compared and discussed.The research results show that SOP has some advantages in aspects of operation cost,degree of recovery,grid voltage and power flow regulation and etc.