Cooperative secondary frequency control of distributed generation: The role of data communication network topology

Abstract

This paper studies the role of the topology of data communication network on the stability of cooperative secondary frequency control in distributed generation power systems. In order to implement a distributed control approach, local controllers should share their data over a data communication network whose structure is not necessarily the same as the physical power network. Although the parameters of generation units are often fixed and set by the manufacturing process, the structure of data communication network is flexible and can be considered as a tunable design variable. In this work, we first derive stability condition for the distributed secondary frequency control that is composed of two parts; one part coming from dynamics of the individual generation units, and the other part from the structure of data communication network. We then introduce a metric that shows the contribution of the network on the stability of secondary frequency control system. This metric is independent of the individual generation units, and depends only on the structure of the data communication network. Using this metric, the stabilization effect of synthetic networks (with scale-free and small world structures) on the secondary frequency control system is studied. Simulations verify the acceptable performance of the proposed metric.