Font Size: a A A

Study On Optimization Reconfiguration And Service Restoration Reconfiguration For Distribution Network With Distributed Generation

Posted on:2018-12-25Degree:MasterType:Thesis
Country:ChinaCandidate:H F HongFull Text:PDF
GTID:2322330512477350Subject:Power system and its automation
Abstract/Summary:PDF Full Text Request
Since the 21st century,the rapid development of social economy has been accompanied by sharp consumption of coal,oil,natural gas and other traditional energy.Human need to seek for renewable energy as a substitute.As the technology of distributed generations,such as photovoltaic power,wind power,fuel cell and micro gas turbine,has become increasingly mature,more and more distributed generations are applied to the distribution network,which has significant impacts on different aspects of the distribution network.This thesis focuses on two problems of optimization reconfiguration and service restoration reconfiguration for distribution network with distributed generation.The main work includes:(1)All substation buses in the distribution network are merged to a root node equivalently,sectionalizing switches and tie switches are equivalent to edges,and feeders between switches,distribution transformers,loads are equivalent to nodes.As such,the whole distribution network can be depicted as an undirected graph.Considering the structural characteristic of 'closed-loop design and open-loop operation' of the distribution network,its radial operational structure is depicted by the tree graph.(2)For the optimization reconfiguration of distribution network with distributed generation,the charge states of nodes remain the same before and after reconfiguration.The 'virtual demand'is used to ensure that all charged nodes are connected to a certain substation power source node in the same connected graph.Coupled with the quantitative relation constraint,namely the number of closed branches equals the total number of nodes minus the number of substation power source nodes,the radial structure of distribution network can be ensured.The mathematical model for optimization reconfiguration with the aim of active power loss reduction is proposed and the chain constraint for annular branch subgraphs is added to improve the computational efficiency.Test results of the PG&E 69-bus distribution system verify the feasibility of the proposed model.(3)For the service restoration reconfiguration of distribution network with distributed generation,there may be unenergized nodes or electric islands in the network after reconfiguration.By defining the 'virtual node' and 'virtual branch' as well as modifying properties of the 'virtual demand',the radial structure of each electric island is guaranteed.The mathematical model for service restoration reconfiguration with the aim of maximizing critical loads is proposed.Taking the controllability of loads into account,two scenarios of whether types of distributed generation are considered or not are tested on the PG&E 69-bus distribution system,and simulation results validate the effectiveness of the proposed model.
Keywords/Search Tags:distributed generation, distribution network, optimization reconfiguration, service restoration reconfiguration, undirected graph, tree
PDF Full Text Request
Related items