This paper presents a study on protection coordination of overcurrent relays (OCRs) in a distributed system by considering its different operating modes. Two different case studies which are considered in present work for protection coordination include: (i) DG interfaced distribution system in grid connected mode and (ii) DG interfaced distribution system in islanded mode of operation. The pro...

In terms of high penetration of distributed energy resources, power systems undergo challenges on aspects of their operation, stability and control issues. Microgrids gained a lot of research interest because they have a promising future to integrate the distributed energy resources into the power systems, reduce greenhouse gas emissions and increase the reliability and security of the power sy...

Renewable energy sources, like wind and photovoltaic (PV) power plants can be used to provide grid-friendly services in the form of additional active and reactive control for frequency and voltage regulation respectively. Current wind and PV power systems are operated in simply an energy supply mode and are not required to participate in ancillary power services. These services will become crit...

Microgrids comprise low voltage distribution systems with distributed energy resources (DER) and controllable loads which can operate connected to the medium voltage grid or islanded in a controlled coordinated way. This concept aims to move from “connect and forget” philosophy towards an integration of DER. Microgrids are expected to provide environmental and economic benefits for endcustomers...

Droop schemes are usually applied to the control of distributed generators (DGs) in microgrids (MGs) to realize proportional power sharing. The objective might, however, not suit MGs well for economic reasons. Addressing that issue, this paper proposes an alternative droop scheme for reducing the total active generation costs (TAGC). Optimal economic operation, DGs’ capacity limitations and sys...

This study proposes a hierarchical control structure for smooth transition of multi-bus microgrids from islanded mode to grid-connected mode. The proposed uses an average consensus protocol the secondary layer and Andronov-Hopf virtual oscillator as primary controller. method enhances power-sharing accuracy among DGs in normal operation. A synchronization strategy is embedded into force MG-side...