Research On Wireless Sensor Networks With QoS For Smart Distribution Grid Communication Application

Recently, Researches on Wireless Sensor Networks (WSNs) in Power Grid communicationwere supported by National Natural Science Foundation of China, U.S. National Science Foundation,and European Seventh Framework Programme (FP7). In2010,“NIST Framework and Roadmap forSmart Grid Interoperability Standards” lists IEEE802.15.4as one of supported standards. WSNshave been widely recognized as a promising technology that brings signification advantage in SmartDistribution Grid (SDG) Communication.Actually, WSNs in SDG high-performance Communications is a kind of multi-objectiveharmonizing optimization problem of uncertainty process with Quality of Service(QoS)requirements, such as real-time and reliability. The main problems need to be resolved are:1.Improving IEEE802.15.4MAC layer protocols channel contention and embedded QoS functionwithout additional overhead traffic.2. Increasing uncertainty dynamic change of traffic and wirelesslinks estimate functions and building a QoS Guarantee Control routing protocol to satisfy therequirements of QoS.3. Specifying design method of network nodes layout and topological structureand optimizing WSNs structure to match with Distribution Grid architecture. To address theseproblems, Basic theory and method for the entire WSNs application in SDG High-performanceCommunications are researched by building network structure and link quality model, contentionstatement model either in node or between nodes, and network performance analysis model. Theresearches provide meaningful insights about exploring the improvement of WSNs performance, andalso have theoretical significance and practical value.The main works can be summarized as blow:(1) The theoretic computational formula and design method of nodes layout and topology forWSNs in SDG are given. According to the requirement of communication of SDG high-performanceCommunications and the uncertain environment feature in which SDG device located, the distance,density, number of nodes and network cover area computational formula are given by buildingWSNs link quality model and networks structure model. It provides theoretical basis of nodes layoutand topological for WSNs in SDG.(2) QoS-MAC protocol algorithm based on unfair competition of WSNs in SDG is proposed.According to the different kinds of real-time data requirement of SDG communication, an enhancedIEEE802.15.4MAC layer protocols embedded QoS feature are proposed without any overhead traffic. The simulation results show that the protocol satisfies all kinds of data with differentreal-time requirement, and in the meantime, MAC layer performance is kept.(3) The MAC layer performance analysis mathematical model is built for WSNs in SDG. Thenode and channel analysis method is setup by building Markov statement buffer and radio channelcompetition statement mathematical model, to resolve the mathematical description problem ofQoS-MAC protocol performance. Simulation results show that this model can be used for WSNsperformance analysis.(4) A QoS guarantee control routing protocol is proposed. Based on the “estimate, decision, andexecute” method, the network resource are effective distributed and the network congest is avoid byestimating uncertainty dynamic change of traffic and wireless links, optimizing routing path choose,and introducing Classification, Queuing and Scheduling management. The simulation result indicatethat the method can optimize routing protocol to satisfy the end-to-end transmission requirement ofall kinds SDG traffic.(5) The WSNs in SDG scenario is designed and simulated. In the QualNet network simulationsoftware, the scenario with the proposed WSNs structure, the QoS-MAC protocol and QoSguarantee control routing protocol is designed. The simulation parameter setting and protocolmodification method are also given. According to the SDG terminal device communication data rate,end-to-end communication QoS (delay and reliability) performances are tested. The simulationresults show that: the researches of entire theory method can satisfy the requirement of SDGcommunication.(6) The actual example of project realization. According to communication environment andrequirements of Distribution Information Management System (DIMS) in huangshan PowerCompany, the actual example of project is realized by designing the WSNs in SDG topology,developing the WSNs end-device, router and coordinator, embedding QoS-MAC protocol and QoSguarantee control routing protocol, and designing the gateway management software whichconnected with DIMS.The actual project test and simulation test results indicate that, the basic theory research and thegiven design method in this paper are adaptive to the QoS performance requirements of SDG datatransmission, and also achieved expected goal of WSNs high-performance communication in SDG.