Research On Survivability Analysis Method Of Medium Voltage Distribution Network Topology

The optimization design of the network structure for medium voltage distribution network, which is the link between the power system with the user, has very important significance for the security, reliability, economic operation of power system. Traditional research methods are mainly to improve the stability and reliability of the network structure, reduce the network loss of distribution network, and accomplish load balancing. Besides, the relevant data which traditional research methods need is complicated and changeable. Meanwhile, the relevant research of traditional methods basically stays on the level of the reliability analysis of the electrical equipments, while ignoring the impact of the network topology. With the expanding scale of medium voltage distribution network, it is becoming increasingly concerned to improve the survivability performance and enhance the sustainable supply capacity of the medium voltage distribution network in emergencies.Network survivability refers to the ability that the network can ensure critical services completed effectively by its own regulation and all services restored as soon as possible in the presence of external attacks or internal faults. Network survivability is the use of the entire network connectivity from the perspective of the network topology to characterize the safety and reliability of the network structure. Based on complex network theory, introducing the survivability analysis method of complex network into the topology analysis of medium voltage distribution network, which makes much sense to discover the defects of the network structure and improve the safety and reliability of the network structure as well as provide guidance to the construction planning of power grid.This paper introduced survivability analysis theory in complex network into the network structure optimization of medium voltage distribution network and got some achievements. Firstly, the paper verified the pressure the applicability of complex network theory in the topological analysis of medium voltage distribution network through the complexity analysis of medium voltage distribution network topology. Secondly, based on the similarity between medium voltage distribution network and complex networks, this paper presented the definition of topology metrics which could be the good manifestation of the structure characteristics of medium voltage distribution network. Furthermore, based on the topological characteristics of medium voltage distribution network, the paper established survivability analysis model and accomplished survivability assessment of varieties by the survivability metric defined above. Moreover, this paper established survivability optimization model based on the topology features and operating characteristics of medium voltage distribution network, and got network topologies that had better flexibility, security and reliability. Finally, this paper analysed comparatively the topological characteristics of the network structure and network elements as well as the electrical characteristics of the entire network before and after optimization.The introduction of network survivability and the use of complex network survivability analysis method for the topology analysis of medium voltage distribution network, which can not only simplify the traditional analysis methods, but also effectively improve the safety and reliability of the entire network from the perspective of topological analysis and put forward a new way for the optimization of medium voltage distribution network structure.