Optimization of topological reconfiguration by transmission line switching for damping inter-area oscillations in power systems.

Abstract

Intentional grid topology change is sometimes used in power system operations to control voltages, improve the net transfer capacities, and even to boost system reliability. As a consequence of topological change by transmission line switching, the power system may be subjected to inter-area oscillations which could impair system integrity in terms of small signal instability. This study has employed quadratic eigenvalue analysis to confirm that topological reconfiguration through transmission line switching can be used to control system voltages especially during high voltage regimes. It has further confirmed that topological reconfiguration when implemented without consideration of system stability, results in inter-area oscillations or in worst cases, in actual instability. This work has therefore proposed a method which uses multi-objective particle swarm optimization algorithm to optimize implementation of topological reconfiguration during voltage control to avoid inter-area oscillatory instability. In this proposed method, the optimization algorithm specifies which lines are to be switched off but at the same time improves small signal stability in the whole network. The proposed method has been tested in the IEEE 30-bus, IEEE 39-bus, and IEEE 68-bus models. The results indicate that when an optimized transmission switching is implemented, small signal stability is improved alongside voltage control and can save power system operators from relying on intuition which is prone to human errors as they make operational decisions