Research On Centralized-Distributed Coordinated Protection And Control Method For Distribution Network Based On Dynamic Topology Analysis

In the context of distributed energy penetration and complicated network connection,the distribution network has presented new characteristics: various network topologies,complicated equipment configurations and variable operation modes,which brings challenges to the distribution network protection and control.To meet the requirements of distribution network protection and control under the new situation,this paper proposes a centralized-distributed coordinated protection and control method based on dynamic topology analysis.This method effectively improves the protection and control performance of distribution network and can adapt to the complex requirements of various network connection,equipment configuration and operation mode change.The proposed distribution network protection control architecture and principle algorithm have passed the RTDS simulation test.Further,the author cooperated with relay protection manufactures and developed a new generation of distribution network protection and control system,which was put into operation in a distribution network of China Southern Power Grid.Major work includes:(1)Aiming at the new requirements for protection and control of distribution network,a centralized-distributed coordinated architecture,including the substation layer,the communication layer and the terminal layer,is designed in this paper.An implement method of centralized optimization decision and distributed backup protection is proposed.Eventually,a network topology description model based on graph theory is established.(2)A centralized protection and control method based on the status subgraph is proposed.Based on the network description model,the protection and control methods for the whole process of the fault identification,fault removal,fault isolation and network self-healing in the distribution network are studied.A load intertripping scheme based on branch sensitivity analysis is studied to solve the power/line overload problem.A case study has verified the effectiveness of the method,which can help to meet the self-adaptation to the network topology,equipment configuration and operation mode for the distribution network protection and control system.(3)A distributed protection and control method based on the coordination subgraph is proposed.The distribution network protection and control substation transmits the current setting values and operation time limit information for each protection and control terminal via the network.The protection and control terminals show good coordination characteristics,and can adapt to the changes of network topology.When network fault happens,the distribution network protection and control terminal can quickly and accurately remove and isolate the fault region based on the current setting values and operation time limit information,ensuring the selectivity and reliability of the protection,and can realize power restoration timely for the normal region,improving the reliability of power supply.(4)In order to realize the main research achievements of this paper,a centralized-distributed coordinated distribution network protection and control system is developed,including the distribution network protection control substation and distribution network protection control terminal.A RTDS test of developed system was carried out,whose results were all qualified.This system was installed in a distribution network of China Southern Power Grid for a trial run.And the application results were acceptable.This research is supported by the National Natural Science Foundation of China(51577073).The research achievement of this paper has been applied in the engineering of China Southern Power Grid,which has gained a satisfactory profit for technology and economy.