The Static Voltage Stability Analysis Based On The Admittance Model In Load

Power system voltage stability has been recognized as one of the most import topics in the analysis of the power system.For the development of the power system and load,the grid interconnections become much more closer.Several voltage collapse accidents has been taken place recently.More attention has been paid to the problem of voltage stabiliy.The maximum power method is one of the main methods in the static voltage stability analysis area,and its focus is the determination of the steady state voltage stability limit.The singular problem of Jacobian matrix around SNB(Saddle Node Bifurcation) is the difficulty of the maximum power method.Continuation power flow algorithm,load admittance model method, nonlinear programming method have been introduced to solve the porblem.This paper concentrates on the static voltage stability.After the summary of the predecessors' literature,the definition and classification of the voltage stability is introduced,and the Algorithms of the voltage stability are listed.In accordance with the singularity of the Jacobian matrix near the SNB,this paper deals with the load admittance model algorithm.The traditional load addmittance model algorithm is introduced.The relationship between the character roots'distribution of the the Jacobian matrix and the matrix singularity is stated.It has improved that transforming the load's reactive power into suscepitance form can slow the movement of the character roots of the Jacobian matrix to the coordinate origin,and improve the convergence of the power flow equation.In terms of some node's convergence of the power flow equation which is not effective with the traditional load addmittance model algorithm,the traditional load addmittance model algorithm has been improved.After transforming the load's reactive power into suscepitance form, load's active power can be turned into the conductance form.It can slow movement of the character roots of the Jacobian matrix to the coordinate origin again,and make the convergence of the power flow equation better.Python and PSS/E have been used to calculate the IEEE-30 node network,draw the PV curve of several nodes has been drawn.This paper's conclusion authenticated that load addmittance model algorithm is better than the traditional one.