Coordinated decentraized emergency voltage and reactive power control to prevent long term voltage instability in a power system

This paper proposes a decentralized adaptive emergency

control scheme against power system voltage instability.

Decentralized control architecture is proposed by segregating the

system into several local areas or zones based on the concept of

electrical distance. Intelligent agents are assigned in each area to

monitor the bus voltages and generator reactive powers to detect

any threat of voltage collapse and to actuate countermeasures.

A novel performance index has been formulated based on the

load voltage and generator reactive power violations to identify

the severity of disturbance and the risk of system emergency in

each area. The coordination of the timing of the countermeasures

among the agents is achieved through the formulation of the

integral of the performance index. The simplicity and the adaptive

nature of the proposed control scheme to provide countermeasures

against any disturbance make it useful for real-time application.

The robustness of the proposed approach has been validated

through several case studies using the New England 39-bus test

system and a more realistic Nordic32 test system.