Development and application of reliability analysis system for medium and high voltage distribution networks

In order to identify the bottleneck weaknesses of a distribution network so as to improve service reliability of the network by effective upgrading, we developed the power flow calculation based reliability analysis software for high-voltage distribution networks and the fault pervasion algorithm based reliability analysis system for medium-voltage distribution networks. Taking into account multiple factors, including line failure rate, repair time, isolation operation time and switching operation time, the system software can calculate the reliability indices and static security indices of node, feeder and system, and analyze the effect of reliability parameter variation, the influence of component reliability, the sensitivity to component reliability, and the bottleneck weaknesses of distribution networks. Actual application of the systems in calculation and analysis of power flow and reliability of Xi'an and other three regional medium and high voltage distribution networks manifested the bottleneck weaknesses of the networks, and found out various existing problems in reliability management. After effective measures are taken, good social and economic benefits were achieved.