A Distribution Network Reconfiguration Algorithm Based On Least Weight Tree For Service Restoration After Faults

With the development of daily life and production, the customers require higher quality and reliability of a distribution network. To meet with the customers' requirements and reduce the loss of the faults of a distribution network in the power system, there comes the distribution automation system as a new and efficient means of management and technique. The practice proves that the distribution automation system can improve the working efficiency, the quality and reliability of power supply. This can bring benefits to both the customers and the power companies. One of the most important jobs of the distribution automation system is to find the fault location in time and correctly, isolate the fault quickly and restore the power supply when there is fault in a distribution network, i.e. Service Restoration After Faults.Service Restoration After Faults is multi-objective, multi-stage, multi-constraint and none-lineal optimal problem. Its answer is a serial of switching operations to give a superior scheme of service restoration with least times of switching operations, highest reliability and least network loss in the constraint conditions of network connected, network radiation and feeder none-overtaxing.Heuristic Search Algorithm and other approximate methods that have been introduced in many literatures on the distribution network service restoration nowadays are still affected badly by the network construction or have such limitations that the conditions in comprehensive research can't be meet at the sametime. All of those can't make the service restoration done quickly. So those are not completely appropriate for the condition of the real-time requirement in programming service restoration. In this paper a distribution network reconfiguration algorithm based on least weight tree for service restoration after faults.This paper puts forward a distribution network reconfiguration algorithm based on the theory of least weight tree in graph theory. After simplifying the real distribution network on graph theory, this mathematical model consists of minimum network loss, minimum switch loss and the highest network reliability; meanwhile, it also involves the constraint conditions of distribution connectedness, radiation, and power supply. It can give an optimal solution and serial sub-optimal solutions for reconfiguration. The algorithm can use adequately the real-time information in SCADA of the distribution automation to control the switches directly according to the scheme composed of an optimal solution and serial sub-optimal solutions. It can be manipulated clearly and it is also accurate, quick and reliable. Above all, the algorithm has the advantages of economic effect, high efficiency and practicability to fit in the surrounding of the distribution automation, and provide efficient and economic decision.In addition, this paper shows the solution of some special problems such as multiterminal power supply, T-wire connection and fault after failure recovery, which makes the algorithm high adaptive capacity.The distribution network reconfiguration algorithm based on the theory of least weight tree in graph theory is simple, practical and real-time. Its characteristics have been proved by the living example to show this algorithm is superior to the current algorithm on the service restoration of a distribution network.In the last part, the paper analyzes the more requirements in the development of the distribution. In the circumstance of the distribution network's continuously expending and complicating, the service restoration system should be very adaptive and maintainable to meet with the changing of the distribution network. This algorithm in the paper provides a new way to solve the service restoration of adistribution network.