Parallel Evolutionary Algorithm for Coordinated Tuning of Exciter Controllers and a group of Static Var Compensators

The electrical distances between substations are reduced due the dense interconnection of the Power Electric Systems (PES); and, when large contingency occur rapidly affect to neighboring regions producing electromechanical oscillations with low, or negative, damping, followed by a significant degradation of the voltage profile. Then, a coordinated tuning methodology is proposed for simultaneously adjusting exciter controllers of each generator and a specific group of static var compensators belong to a certain multi-machine electric system. The referred static compensators are located into voltage sensitive substations to control the injection of reactive power, for voltage regulating. Exciter controllers, like power system stabilizer and voltage automatic regulator, are located into excitation system of generators to damp electromechanical oscillations. The coordinated tuning problem was considered as an optimization problem, maximizing the minimum damping coefficient of the system, considering at the same time several critical operating conditions. The Genetic Algorithm was used for optimization process and adapted for parallel computing in order to face the large dimensionality of the resulting optimization problem.