Analysis Algorithm for Reliability of Planning Grid

Whether distribution system can rebility operate is mostly decided by the network structure, a reasonable grid structure comes from power network planning. Power network planning is full of the randomness and uncertainty, we can´t get accurate information of distribution transformer from planning grid, which causes some difficulties in distribution system reliability assessment. This paper makes some reasonable assumption basing on analysing features of the planning grid and presents a simple and effective analysis algorithm which takes alternative supply and capacity-limitation into account for the reliability assessment of complex distribution network. This algorithm based on network -equivalent algorithm fully considers breakers, lines, switches, distribution transformers and other equipment failures impacting on the reliability index of distribution network, importantly the proposed algorithm can be well adaptive to different distribution network structures of both over-heading and cable type. The theory and formulas are presented in detail and the validity of the algorithm is verified in a typical 10kV distribution system.