Security Region and Total Supply Capability under N-0 for Urban Distribution Network

In this paper, the model of distribution system security region (DSSR) and total supply capability (TSC) under N-0 security (normal operation constraints) for urban distribution network is proposed, named DSSR0 and TSC0. Firstly, the necessity of studying DSSR0 and TSC0 is analyzed. Secondly, the concepts and mathematical models of DSSR0, TSC0 and TSC0 curve are proposed respectively. DSSR0 is the maximum security operating range of distribution network, inside which are secure operating points, and outside which are insecure operating points. TSC0 is the maximum load supply capability of distribution network, and its connotation is the same as loadability. Finally, the proposed model is verified by case study. The differences and relations of security region and supply capability between N-0 and N-1 are analyzed; and how to use them in operation and planning is also summarized. DSSR0 and TSC0 can help dispatching operators clearly define the “red line” of system operation.