Control of Distributed Generators in Island Mode

Nowadays, the power industry widely uses distributed generators (DG) located in close proximity to energy consumers. These generators can operate both in the isolated (island) mode for allocated load, and in parallel with the centralized electric power system (EPS). The article describes a model of an electric power supply system (EPSS) with turbo- and a diesel-generators (TG and DiesG, respectively) with their respective controllers, as well as the results of modelling the transition of turbo-generators to the island mode upon the loss of connection with a power-feeding electric power system and connection of a diesel-generator. Modelling was performed using the MATLAB simulation software with the Simulink and SimPowerSystems packages. From the modelling results, the following conclusions can be drawn: transition to the island mode and the connection of additional high load, as well as turbo-generator overloading, lead to power-fail and frequency drop in the electric power supply system. Connecting and synchronizing a diesel-generator with a turbo-generator provides the stabilization of voltage and frequency at bus bars of the turbo-generator and of the parameters of the electric power supply system operation. The application of the predictive control approach for turbo-generator controllers, provides for a significant reduction of the system response, reducing the risk of excessive correction and mitigating voltage and frequency fluctuations at the shutdown of the power-feeding electric power system after connecting an additional heavy load.