Patent ID: 6832167
Filing Date: 2004-12-14
Classification: H02J

Abstract:
A method for the identification of weak and/or strong branches of an electric power transmission system which employs known analytical methods appropriate to power flow in nodes and branches of the power transmission system and which analyzes functional relations between active and reactive load for this system, wherein the electric parameters characterizing the nodes and branches of the power transmission system are subjected to computational treatment in order to obtain equations of power flow in all nodes of the system at a first load type or base system load, which is used to calculate complex voltage values in those nodes, and a branch voltage stability system coefficient /cvc/ for an analyzed system branch situated between two receiver nodes, after which the total system load is increased and all operations relating to the determination of the voltage stability coefficient for the analyzed system branch at the predetermined system overload are repeated at a second load type or overload system load, and then the numerical value of one of the branch voltage stability coefficients /cvc(1)/, /cvc(2)/ determined for both types of system load is compared with a threshold value considered to be a safe margin for maintaining voltage stability for the analyzed branch, and the value of the difference between the values of the branch voltage stability coefficients determined for both types of system load is checked whether it is more than, equal to or less than zero, and on the basis of those comparisons the analyzed branch is identified as weak or strong.