Identification of Weak Nodes in Power System Using Conditional Number of Power Flow Jacobian Matrix

Abstract

In power system an important feature is the ability to anticipate Voltage instability, as it helps in splitting the network into islands and system will be in extremis state. Identification of weak nodes in power system may be useful for system operators for actuating suitable controls to prevent voltage instability. Time series evolution of the conditional number of power flow Jacobian matrix is utilized in this paper to identify the weak nodes in the system. If the conditional number value goes beyond the threshold value, then the generators with minimum reactive power margin and loads with maximum change in nodal reactive power loss within the zone are identified. All these generators and nodes within the zone are ranked, the generator with minimum reactive power margin and the node with highest change in nodal reactive power loss in the minimum reactive power margin zone is the weakest node. This methodology is validated in New England 39 bus test system and the simulation results shows that this methodology is effective in identification of weak nodes in the power system.