Patent ID: 6904372
Filing Date: 2005-06-07
Classification: H02J

Abstract:
1. A method for the identification of weak and/or strong nodes of an electric power transmission system, which analyzes functional relations between an active and a reactive load for the system, comprising: subjecting electric parameters characterizing the nodes and branches of the system to computational treatment in order to obtain power flow equations in all nodes of the system at assumed 100 percent system load, using the treatment to calculate complex voltage values in the nodes, using earth as a reference node, calculating node impedance values for all the system's nodes, using the node impedance values to construct a curve /P-Q/ showing a functional relation between reactive load /Q/ and active load /P/ of the system, and for a given each node, individually determining a nodal coefficient of voltage stability as a relative distance between a base load point of the given node and a critical point on the curve /P-Q/ which is situated most closely to the base load point, whereupon a numerical value of the nodal coefficient is compared with a threshold value considered to be a safe margin to maintain voltage stability for the given node, and based on that comparison, the given node is identified as weak or strong.