Line collapse proximity index for prediction of voltage collapse in power systems

► Index is based on generalized ABCD parameters. ► Index takes into account direction and magnitude of real power. ► Index is capable on identifying the critical branches/nodes and weak areas. ► Index can be used for on-line voltage stability assessment. This paper proposes a new index to assess the voltage stability of the system accurately. The index is based upon exact model of transmission system and developed using ABCD parameters of network. One of the important features of the proposed index is that it incorporates the effects of relative directions of active and reactive power flows in the line to predict voltage collapse. The proposed technique is investigated on IEEE 30-bus, and IEEE 118-bus systems to validate its practicability.