Power system reliability in local subsystem co-working with power system network

In this paper the new idea for the reliability calculation is proposed-the analysis in simplified power system network as equivalent of the complex power system. The main programs used for the reliability calculation were tested and the results were verified. The reliability models using in TRELSS and NIEZ programs are described. The economic and technical aspects of the cooperation between local subsystems a national power system are discussed. The results of analysis concerning reliability factors in middle voltage network are discussed particularly from the point of view of possible co-operation between power system dispatcher and utilities.