Optimal reconfiguration for Extra high voltage transmission networks using an enhanced Brute-Force algorithm

Abstract

Over the last decade, Extra high voltage (EHV) transmission networks are becoming excessively meshed to reliably accommodate different types of generation and meet the operational security constraints during steady state and transient conditions. However, excessive meshing, combined with the addition of new power plants, can result in short circuit levels that exceed the capability of switchgear components. As such, there is a growing need to limit, the degree of meshing to accommodate the short circuit capability of the existing network assets, thus avoid catastrophic implications that may lead to very expensive equipment damage and personal safety concerns during fault conditions. Under different network conditions, the operators may have to reconfigure the EHV transmission grid differently to avoid exceeding the short circuit rating of the network assets, while maintaining the grid reliability following the next contingency. This paper proposes a new deterministic optimization model for determining the best EHV transmission network reconfiguration for short circuit relief, while meeting the network steady state and transient security requirements. The optimization model is solved using an enhanced Brute force algorithm that limits the search space, hence improves the computation efficiency of the classical Brute Force technique. To test the accuracy and computation efficiency of the proposed optimization model and enhanced algorithm, the IEEE 39-bus model and a real-size practical EHV network model were used as testbeds. The results demonstrate that the algorithm managed to successfully identify optimum EHV grid reconfiguration that would limit the short circuit levels while satisfying the steady state and transient security requirements mandated by the network operators.