Research On The Reliability Of Distribution System And It's Application

In power system distribution system connect directly to customers. According to Stat.80 percent of the unavailability of supply to a customer are caused by the faults of distribution system. With the increasing electric level of city and country, a more reliable distribution system is required. More and More attention and regard are paid to the reliability of distribution system. Traditional evaluation method for the reliability of distribution system is a failure modes and effects analysis (FMEA), but it could become very verbose when applied to a complex network with overlapping outages. There are minimal path method, minimal cut set method, network equivalence method, fault-traverse technique method and recursive algorithm method etc for the evaluation of the reliability of distribution network recently.Main purpose of this thesis is to study the evaluation of the reliability of distribution network. Add outage expense caused by the failures of network to the target function of distribution network structure planning, and studied it. Finally give out the managing and technical measures to increasing the reliability of distribution system.(1) Evaluation reliability of a complex distribution networkA practical distribution system is usually consist of a general feeder and some subfeeders, each feeder consists of several main sections and several lateral sections, which is relatively complex and impossible to get the reliability indices of each load point. Directly. So first delaminate the network according to the relation of connection as main feeders and subfeeders, then equivalent the affection of subfeeder to it's superior feeder with successive network equivalents as equivalent lateral sections. Using this method to equivalent from the bottom to the general feeder step by step, a complex network with subfeeders is reduced to a simple one feeder radiate distribution system. A Tree configuration is a hiberarchy, which resembles the distribution network in the aspect of structure. Thesis is based on the recursive structure of distribution system, makes a line of the network as a node of the tree, stores a network as a left-child and right-sibling binary tree , thenrealizes successive network equivalents through postorder recursive traversal, and makes complex subfeeders to a equivalent lateral section so reduces a complex multi-layers distribution network to a simple one layer radiate network. Uses Preorder recursive traversal, in the order of node, right-sibling, left-child to calculate reliability indices. The load point s that connect to the feeders could be , calculated the indices directly and the equivalent lateral sections could get the equivalent series component which reflects the affection of the upper layer to the underlayer on the reliability. Using this method step by step and layer by layer will get the reliability indices of all load points. After all the individual load-point indices are calculated could obtain the feeders and system indices.Distribution Reliability calculation software is developed on the windows 2000 platform by using Visual C++ 6.0. Object orient technology (GOT) is adopted during development. In the development of software components, weather, schedule repair, load transfer, and operation mode are considered in the algorithm. The outcome includes the reliability indices of individual load point, each feeder and the system.(2) Optimum Distribution Network Structure Planning with Power Outage CostNetwork planning is one of the main aspects of the planning of electric power network. Traditional mathematic model of distribution network planning takes the minimum sum of the cost of operation and construction, and takes the reliability as network test, which doesn't think through the affection of reliability on the structure of network. On the basis of considering the influence of distribution system reliability on the economic value on the consumer side, a new mathematical model with comprehensively considering of investment, operation and loss of the consumer caused...