A NEW AND FAST TECHNIQUE FOR VOLTAGE STABILITY ANALYSIS OF A GRID NETWORK USING SYSTEM VOLTAGE SPACE

The relative positions of the bus voltage phasors in the voltage space of a system depend on the characteristics of and the power flow in, t he transmission network. When the voltage space of the system is exami ned with respect to the ''centroid'' of the system voltage space, it i s possible to identify the loadability of buses and rank them accordin gly. (The term centroid is used owing to the lack of a better word.) A technique based an concepts applied to equilibrium analysis of rigid bodies is developed to determine the centroid voltage of the system vo ltage space and centroid voltage of the generator voltage space. The r elative positions of the bus voltage phasors with respect to the centr oid voltage of the system voltage space and centroid voltage of the ge nerator voltage space are used to identify and compute a voltage stabi lity index for the load buses in the system. This technique is compare d with three other techniques proposed in the literature. The relative merits of all the techniques are discussed and sample results are pro vided. The results indicate that the proposed technique is simple, rel iable and fast, requiring only the examination of the system voltage s pace with respect to the centroid voltages. The proposed technique is ideally suited for on-line EMS applications in an Energy Control Centr e as it requires only the output of the state estimator. (C) 1998 Else vier Science Ltd. All rights reserved.