In future power systems, widespread small-scale energy storage systems (ESSs) can be aggregated to provide ancillary services. In this context, a new load frequency control scheme which incorporates the energy storage aggregator (ESA) and its associated disturbance observer is proposed. The disturbance observer is designed to supplement the secondary frequency control for the ESA, therefore the system frequency response and recovery can be improved. Within the ESA, a finite-time leader-follower consensus algorithm is proposed to control the small-scale ESSs via sparse communication networks. This algorithm ensures that the ESA tracks the frequency control signals, while the state-of-charge among each ESS is balanced in finite-time. The external characteristics of the ESA will resemble to that of one large-scale ESS. Numerical examples demonstrate the convergence of the ESA under different communication graphs. The effectiveness of the entire scheme for power system frequency control is validated under a variety of scenarios that include contingency and normal operation.

Internet-of-Things concepts are evolving the power systems to the Energy Internet paradigm. Microgrids (MGs), as the basic elements in an Energy Internet, are expected to be controlled in a more flexible and corporate manner. This paper proposes a novel distributed control scheme for multi-agent systems (MASs) governed MGs in future Energy Internet. The control objectives are frequency/voltage restoration and proportional power sharing. The proposed control scheme considers both intra and inter MASs interaction, which offers group plug-and-play capability of distributed generators (DGs). The stability and communication delay issues in the control framework are also analysed. A multi-site implementation framework is presented to explain the agent structure as well as data exchange in local area networks and the cloud server. Then a cyber hardware-in-the-loop (C-HiL) experiment is conducted to validate the proposed control methods and multi-site implementation. The experimental results prove the effectiveness and application potentials of the proposed approach.

The reactive power of the photovoltaic (PV) inverters has great potential for voltage regulation of distribution networks. In this paper, a new three-level coordinated control method for PV inverters is proposed to address network voltage fluctuation and violation issues. In Level I, a ramp-rate control is designed to smooth the network voltage fluctuations, while in Level II, a droop control is designed to alleviate the network voltage deviations. If the local compensation provided by Level I and II is not enough to regulate the network voltages within the required limits, the Level III control based on dynamic average consensus can respond and share the reactive power requirement among other inverters in a distributed way. The proposed control method can smooth the voltage profiles, restrain the voltage rise/drop problem, and coordinate all PV inverters in real-time when there is no feasible local solution. The stability analysis of the proposed three-level coordinated control for network voltage regulation is provided. The power hardware-in-the-loop (PHIL) experiment has been conducted for validating the proposed control method under various scenarios.

The integration of smart grid technologies in interconnected power system networks presents multiple challenges for the power industry and the scientific community. To address these challenges, researchers are creating new methods for the validation of: control, interoperability, reliability of Internet of Things systems, distributed energy resources, modern power equipment for applications covering power system stability, operation, control, and cybersecurity. Novel methods for laboratory testing of electrical power systems incorporate novel simulation techniques spanning real-time simulation, Power Hardware-in-the-Loop, Controller Hardware-in-the-Loop, Power System-in-the-Loop, and co-simulation technologies. These methods directly support the acceleration of electrical systems and power electronics component research by validating technological solutions in high-fidelity environments. In this paper, members of the Survey of Smart Grid International Research Facility Network task on Advanced Laboratory Testing Methods present a review of methods, test procedures, studies, and experiences employing advanced laboratory techniques for validation of range of research and development prototypes and novel power system solutions.

This paper presents a novel approach for realizing coordinated control of Distributed Energy Resources (DERs) based on cloud-hosted and edge-hosted digital twins (DTs) of DERs. DERs are playing an increasingly important role in supporting the frequency regulation of power systems with massive integration of renewable resources. However, due to the significant differences in DERs’ capability and characteristics, individual and un-coordinated responses from DERs could lead to a less effective overall response with undesirable traits, e.g. slow response, severe overshoots, etc. Therefore, the coordination of DERs is critical to ensure the desirable aggregated overall response. A major shortcoming of conventional centralized or distributed approaches is their significant reliance on real-time communications. This paper addresses the challenges by the application of DTs that can be hosted in the cloud for the centralized control approach and the edge for the distributed approach to minimize the need for real-time communications, while being able to achieve the overall coordination among DERs. The proposed DT-based coordinated control is validated using a realistic real-time simulation test setup, and the results demonstrate that the DT-based coordinated control can significantly improve the aggregated DERs’ response, thus offering effective support to the grid during contingency events.