Perspectives for the coordinated design of damping controllers in restructured power systems

This paper presents a discussion about the future perspectives of the coordinated design of controllers to damp low frequency electromechanical oscillations in power systems. Most of the restructuring processes that are occurring in power systems throughout the world have a common tendency to stimulate privately owned distributed generation. In this scenario, if the task of designing the controllers is left to the generating companies, it will probably become increasingly difficult for different companies to coordinate their new controllers with the already existing ones. However, since the systems will probably be required to operate under tighter restrictions imposed by the power markets, a good coordinated action of the controllers owned by different companies will constitute a sine qua non condition for an acceptable small-signal stability margin for the system. The paper presents an example of possible dangerous situations which may arise if coordination is neglected in the restructured systems. Then, based on the conclusion that a coordinated design of damping controllers is unavoidable, the paper discusses some alternatives for carrying out such design in the new framework.