Research On The Observations And Mechanisms Of Distribution System Security Region

As an important part of the smart grid,the distribution system has a major impact on the security of urban power supply.How to describe its security is extremely important.Distribution System Security Region(DSSR)is a closed set of all the operating states(operating points)in the state space that meet the security criteria.It can accurately describe the maximum allowable operating range of the system under a given security criterion.This dissertation focuses on the observation methods and mechanism of DSSR.The main contributions include:1.The formation of the distribution network security boundary in two-dimensional state space is revealed.The mechanism and quantity formulas of the diagonal and straight-line boundaries are discussed.The 2D view of security boundary matching seven typical distribution networks is summarized.The boundary number can be calculated and the shape of the 2D view of security boundary can be determined preliminarily according to the contact relationship of the observation feeders.There is no need to simulate or write boundary expressions.2.DSSR of distribution network connection mode is observed directly in full dimension for the first time,and the influence of different connection mode on DSSR is also studied.For the distribution network with multiple transfer modes,its security region is concave,and there is "Valley";after the flexible transformation,its security region makes up the "Valley",and the region is fuller.3.The concept and method of DSSR full-dimensional indirect observation are proposed.The effect mechanism of distribution network structure and bottleneck components on DSSR is studied.With the increase of bottleneck component capacity and network symmetry,DSSR can be improved,the shape is more round,the scope is increased,and the dents are reduced.4.The method of DSSR integrated observation is proposed,of which the main idea is “first overall,then local;first indirect,then direct”.The advantages,disadvantages and application occasions of the existing DSSR observation methods are listed,then the relationship between direct observation and indirect observation is explored.5.A novel method based on DSSR for distribution network security situational awareness is proposed.It is the first time to apply DSSR theory to the security situational awareness of distribution network,which inherits the advantages of the domain method,reduces the calculation amount,and simultaneously considers the N-0 security and N-1 security.It can be better applied to online monitoring and real-time prediction of security in distribution network.