Research On Algorithms For Static Security Analysis In Power System Based On Sensitivity Method

With the economy and society developing,the scale and capacity of power sys-tem,together with the complexity of power grid,are increasing,which leads to a greater chance of system failure rate.It has always been people's goal to keep this tremendous system operating safely and steadily.Static security analysis is one of the most important measure to enhance the safty of power system.What it studies is that when equipments are out of service,whether or not they would cause off-limit volt-age and branch power flow,and how to provide quickly the correcting strategy to clear the off-limit phenomina to continue system's safe and steady operation.Centreing on static security analysis in this paper,firstly,in terms of the draw-backs of the traditional storing form of admittance matrix and solving method of lin-ear equations,a novel random and asymmetric storing form for non-zero elements and a new gaussian elimination based on it are proposed.Secondly,DC power flow algorithm,Newton-Raphson algorithm and P-Q decomposition algorithm are intro-duced,and on the basis of each of which,some related improved algorithms able to increase the efficiency of storage and calculation are presented.Thirdly,by calculat-ing the sensitivity matrices through the data from initial power flow calculation,3 kinds of line outage simulation algorithms corresponding to various power flow algo-rithms are deduced.Finally,3 voltage and 2 branch power flow sensitivity matrices are put forward,which determine which correcting method to use based on the values of those matrices.And as to off-limit voltage correction,a method determining the most sensitive node in one area is provided;as to off-limit brach power flow,an ad-justment method of equal and opposite quantities in pairs for correcting.Adopting the C++program language,though the IEEE node systems,it is vali-dated that the algorithms in this paper are fast,accurate and effective.