Evaluation Of Distribution Network Capability Based On Total Supply Capability And Distribution System Security Region

With the informatization and automation of smart distribution system,load transfer among transformers will be faster,which benefits secure and efficient distribution system operation.The total supply capability(TSC)theory and distribution system security region(DSSR)theory based on N-1 guideline are proved to be powerful techniques of such kind.However,TSC can only be reached under some specific load conditions,which can not reflect the supply capability under other conditions.In order to solve this issue,this paper proposed a new approach to evaluate the capability of distribution system based on the TSC and DSSR theory,which can provide important reference for distribution system planning.First,the concept,indices and sampling method of boundary supply capability(BSC)were proposed.BSC is defined as the total load of the critical boundary point,which can reflect the efficiency of distribution system at the point.The supply capability distribution consists of BSC of all critical boundary points,and it can describe the supply capability of distribution system completely.TSC is the maximum of BSCs.The sampling method includes three steps:(1)obtain a set of boundary points by sampling;(2)calculate the BSC value of each point;(3)analyze the BSC set to obtain sorted BSC curve,BSC proportion distribution curve,and BSC indices.Second,this paper proposed the concept,indices and Monte Carlo simulation based algorithm of DSSR volume.DSSR volume indicates the size of security operation range,and it can reflect the security performance of a distribution system.The bigger DSSR volume is,the better the security performance of the distribution system will be,and the more balanced the safety margin in all direction will be.Finally,the effectiveness of proposed concept,indices and algorithm of BSC and DSSR volume was verified by two cases.The results demonstrate that BSC and DSSR volume can evaluate the distribution system capability accurately.The distribution system whose feeder links are more balance has higher efficiency and better security performance.Moreover,the effects of penetration and location of distribution generation(DG)on DSSR volume were analyzed,which can provide significant reference for distribution system planning.