The whole-process reliability evaluation of power system including generation, transmission, transformation and distribution

Aiming at the problem that using current reliability evaluation indices, which can reflect only one segment of power system, for power system planning leads to partial planning results and is hard to achieve the goal of global programming, this paper proposes an approach to evaluate the reliability of the entire power system, considering the effect of generation, transmission, transformation and distribution system. The power supply reliability not only depends on the structure of the distribution system, but also on the main grid. In the proposed evaluation procedure electrical connection of substation is firstly equated to some equivalent branches based on minimal cut-set method. Then Monte Carlo Simulation (MCS) is used to assess the reliability of generation and transmission composite system and substation system simultaneously by sampling and to obtain hierarchical available capacities and probabilities. Finally, the hierarchical reliability indices of the main grid are used as multi-state equivalent sources to assess the distribution system reliability. The proposed method is tested using a system constituted by the IEEE RTS 79 and feeder of IEEE RBTS-bus6. The results show that the main grid has obvious influence on the reliability of distribution system, and the proposed method can provide more details for system planning and operation.