Effects Of Distribution Automation On Distribution Network Reliability Research

Distribution network is the terminal link between power and users. The rationality and automaticity of distribution network structure directly determine power supply reliability. Promoting the construction of distribution automation can realize fault location, isolation and restoring power supply for the users in trouble-free section rapidly, which is a great help to improving reliability. However, the construction of distribution automation facing the problem that the space truss structure of distribution network is weak and the implementation of distribution automation will also bring short time power outages to users. To solve these problems, the paper researches the optimization planning method of distribution network, proposes the reliability index calculation method under different distribution network automation mode, and then analyzes the influence of distribution network automation on short time power outages deeply. Specific research contents and achievements include:1) The definition of "unit" is put forward, and then the method presents three types of data structures, namely unit data structure, element data structure and load point data structure to represent the topological structure of distribution network, the parameters of elements and load points. When fault occurs, the distribution network will be divided into four types of units, namely fault unit forward unit, backward unit and unaffected unit. The failure mode effects analysis table which records the effects of each failure element on each load is established. On this basis, the reliability index of the distribution network is calculated by Monte-Carlo simulation. Taking the IEEE RBTS BUS6 for example, the method is programmed on the MATLAB platform. By results comparison, the validity of the proposed method is verified.2) Establishing the mathematic model and data structure for the tie line optimization problem. The objective function is the minimum investment cost and the constraints include the load transfer capability and the length of the tie line.On the basis of the contact cost matrix, the distribution network line contact problem is likened to the assignment problem. For the differences between the two problems, the handling method is setting the elements in the contact cost matrix that symmetrical to the zero elements to zero, and the paper realizes the method through changing some stems in the Hungarian method. Optimizing the lines in the example distribution network by the proposed algorithm, the results show that the lines are in one-on-one contact form, and the investment cost is the minimum.3) Analyzing the radiation network and ring network fault handling process under two types of modes. Researching the influences of local automatic mode and global automatic mode on short time power outages and longtime power outages dentally. Improving the code structure of the unit by increasing the level number to describe switch action sequence. and then a table to record different user power outage situation under different automatic mode is set up. Based on the simulation method, the steps of reliability index calculation method under different automatic mode is put forword. Calculating the reliability indices of the example distribution network under different automatic mode, and the influence of distribution automation on distribution network reliability is analyzed quantitatively.