High-speed control framework to reduce system awareness delay in microgrids: A conceptual approach

Microgrid is a power system that integrates distributed generators (DGs) including renewable resources and distributed energy storage (DES) devices to supply power to both critical and non-critical types of distributed loads. As for the operation, microgrid should operate in the grid-connected mode as well as in the islanded mode and should be able to switch between these two modes safely and reliably. Overall expectation is that microgrids should deliver a high-quality power efficiently and reliably, in both modes of operation. In recent years, technological development has allowed collection of data related to the operation of power delivery system at a very high speed using instruments such as Phasor Measurement Units (PMUs). Therefore, microgrid control system should be capable of receiving and analyzing these high speed data and then be able to send a control signal in due time, that is before next set of data arrives for processing. Thus, the control system should be able to operate at high frequency to match the data generation speed. In a microgrid, integration of DGs and power electronic interfaces is expected to reduce the system inertia. But that may not be enough for modern day power delivery system with higher speed data collection instruments. Therefore, the control system needs to be designed with higher speed for reliable operation of the microgrid. We are working on the development of control schemes for high frequency applications through the development of model and feedback control system. In this paper, we will discuss some of the initial works including simulation results to demonstrate the need for reduced system inertia for better microgrid operation and maintenance, since higher system inertia can adversely affects the demand and/or fault response time. Therefore, to lower system inertia the system awareness delay time needs to be reduced. This is especially important to attain seamless transition between the two modes of operation, for operation in islanded mode, and to meet the demand of critical loads.