Network Topology of Urban Grid Considering N-1-1 Criterion

Urban area is the major load centre of power system. To meet N-1-1 criterion is important for an urban grid with the requirement of high power supply reliability. The considerations of N-1-1 criterion in overseas developed areas are compared in this paper. The impact of the configuration of substations and the inter-connections on power supply reliability is analysed for the grid under N-1-1 condition. In addition, the urban network topology which can meet the N-1-1 criterion of British ER P2/6 guideline is discussed. A more stringent N-1-1 criterion and corresponding network topology is proposed to accommodate the development of urban grid.