Basic Research Of Wireless Sensor Networks And Applications In Power System

The fast evolution of computer technology, sensor technology, MEMS and modern wireless communication technology has impelled development of wireless sensor networks. Wireless sensor networks provide a new platform to sense the world, process the data. It is widely applied in lots of fields, such as military defense, industry control, agriculture control, city management, biomedicine, rushing to deal with an emergency, rescue, remote control to danger zone, manufacture et al. Wireless sensor networks are consist of a large number of nodes which can be capable of communicating, computing and cooperation in ad hoc model. Combined with national natural science foundation of China and based on the status quo of the power system informationization , some basis research of large-scale wireless sensor networks applied in power system are carried through..In this dissertation, the following topics are investigated for providing a new reliable, high quality communication platform:(a) For the requirement of QoS (Reliability, delay etc) in power system, performance of wireless sensor networks should be testified by experiments. Till recently, performance of communication networks are mostly tested by simulation software, such as NS, OPNET etc. But a lot of practical factors can't be taken into account in simulation software. For examples: obstacles, electromagnetic interferences, and so on. Utilized NDIS(Network Driver Interface Specification) intermediate driver and Passthru architecture, a simulation testing platform of wireless ad hoc networks is constructed. The characteristic and application prospects of the platform are introduced. By the platform, the performance of a wireless ad hoc network can be validated only adopting PC or portable computer.(b) Topology control is one of key problem of a wireless sensor network. The primary aim of the topology control is to reduced the energy consumption, increase the lifetime, decrease the communication interference of the network, and provide groundwork for routing protocols. A localized discrete distribution topology-control algorithm (LDDTA) of wireless sensor networks is presented. The LDDTA strongly decreased the redundancy links of wireless sensor networks. Firstly, the topology links of the wireless sensor networks is discreted and formed a number of isolated network island topologies, which are called isolated network island (ISI). These network island have the bounded node degree and the best link qualities for each node. Then, all isolated network islands are linked by intersubgraph algorithm which minimizes the power energy consumption between the isolated network islands. Simulation results show advantages of the algorithm.(c) Energy constraint of wireless sensor network is also one of the most demanding challenges in actual applications. Generally, there are two ways to supply the power of wireless sensor network: supply by batteries or obtain energy from surroundings. Energy can be obtained from the surroundings by photovoltaic cells, vibration, or an iron core winding which surrounds a line conductor. For the constraint of node's size, the average supplying power of nodes is very limited. By analyzing the working model of sensor nodes in power system, an energy consumption model is constructed and a hybrid genetic algorithm is used to optimize the energy consumption. The model provides an effective reference of working pattern for wireless sensor networks in power system. At the same time, optimal energy method for task allocation is analyzed by GA.(d) An architecture, installation and deployment scheme of wireless sensor network applied in power system is presented for power fault detection and location. Fault detection, location and sampling mechanism of wireless sensor networks are investigated in power system. The reliability of wireless sensor networks in power system is studies and a reliability scheme oriented to transactions is presented. (e) Time synchronization is an important infrastructure for coordinated work to a wireless sensor network because it is a distribution system. Aimed at the wireless sensor network applied in power system fault detection, a new time synchronization scheme is presented. When a fault occurs in the distribution power system, traveling-waves will come into being which spread along the power lines. The new time synchronization scheme is based on the traveling-waves. Performance analyses and simulation results demonstrate that the proposed scheme meet the requirements in power system.(f) Collaboration is one of the key problem for a wireless sensor network in practice. Based on the characteristic of the wireless sensor network and multi-agents theory, collaboration technique is studied. Utilized organization of the wireless sensor network and based on distribution decision-making, a new power system fault diagnostic scheme is presented.