Enhancing small signal stability of an emerging distribution system by a coordinated controller

The structures of distribution systems are changing due to increasing penetration of distributed generations (DG units) as well as integration of advanced controllers and communication infrastructures. As a result, emerging distribution networks have a number of generators and controllers operating in a closer proximity. Such a proximity of dynamic devices results into modal interactions, which can deteriorate small signal stability of distribution systems. In such a case, a controller must be installed to ensure stability under different operating conditions. This paper presents a robust coordinated damping controller for distribution networks. The controller receives wide area control signal from network and sends supplementary control signals to the DG units. The advantage of the controller is that it can support small signal stability even if some DG units are out of operation. The effectiveness of the controller is tested in a 43-bus industrial distribution network.