Research On The Key Issues In Wireless Integrated Networks Oriented To Smart Distribution Grid

Access network is the weak link of communication system in smart distribution grid (SDG), and there is no single network that provides the quality of service (QoS) with the industrial requirements for the communication services in SDG. The wireless integrated network that supports a variety of wireless access technologies can provide reliable, safe and efficient service for various users, and it is extremely suitable for the access network in SDG. Therefore, the research on the key issues in wireless integrated networks is especially important. The key issues include load balancing (LB) in heterogeneous integrated networks and the routing mechanism in the wireless sensor network (WSN), and two key issues are the crucial factor which influences system resource utilization as well as energy consumption. Consequently, the design of optimize LB strategy in heterogeneous integrated networks and routing mechanism in WSN is a very challenge research project.On the basis of many studies on the communication system in SDG, as well as the model of communication services, a wireless integrated network model for SDG is built. It can not only support an overlapping network with various wireless access technologies on the access layer, but also regard the WSN as the sensor layer to achieve seamless coverage of the future smart grid.Aiming at the problem that the existing LB algorithm failed to consider the requirements of different communication services sufficiently, a LB algorithm based on the matter-element analysis method is proposed from access control perspective. Firstly, a matter model is constructed considering three aspects of the received signal strength, the service blocking probability and the available resource, and we can get the correlation degrees of candidate networks about different grades through matter-element analysis and entropy weight methods. Then, in accordance with the priorities which are ranged from high to low, new communication services in SDG are accessed in turn to the network with the optimal quality. Therefore, the services with different priorities are differently served. Furthermore, considering the condition of the access control strategy and overload network of heterogeneous integrated networks in SDG, a hybrid dynamic LB algorithm is proposed based on the combination of resource borrowing and load transfer schemes. In the first place, the triangle module fusion operator is used to determine which light workload network is suitable for lending the idle resources to the overload one. In order to balance the load of overload networks, the certain services in the overload network are transferred to the light load network with the minimum load rate in the overlapping heterogeneous environment. In the second place, new communication services in SDG are accessed to the network with the maximum available resource rate.Besides, a chain routing algorithm based on Dempster-Shafer (D-S) evidence theory is proposed. First of all, in the chain construction stage, the node which has joined the chain is taken into account, and each one is connected to its nearest node to avoid the generation of long chain. Secondly, in the leader election stage, D-S evidence theory is employed to fuse the two evaluation indexes which are the distance between nodes and the base station as well as the remaining energy of nodes, so that the appropriate leader node is selected. Simulation results show that the network lifetime is greatly extended, while the energy consumption among the nodes can be balanced.