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The distributed and stochastic nature of Renewable Power Sources is certainly forming considerable challenges for the operation of the power system. Specifically, the stability of the system can be jeopardized when the penetration of inverter-based systems is high. Storage and the proper design of controllers is seen as part of the solution for supporting the future expansion of distributed systems. Thus, control strategies need to be designed to provide the appropriate support to the system and be capable of keeping the variation of the frequency within limits to keep the reliability of the system as high as possible. The main challenge is the appropriate parameterization of these distributed controllers and their coordination under the integrated grid approach in securing the stability of the system at all times. In this paper, a smart energy controller is utilized and incorporated into the projection case study for Cyprus’ real distribution grid for the year 2050 to evaluate its behavior and identify possible weaknesses in its usage. It was found that the parameterization and not only the architecture of such controllers is crucial in coping with the frequency variation and stability problem. From the simulation work and recorded results, it was observed that the smart energy controllers can maintain frequency variation within the desirable range when the parametrization of the controllers is chosen appropriately. This specific observation highlights the need to evaluate and configure the smart controllers while operating in the field, and possibly further research is required to provide the advanced capability to such systems to adjust dynamically during field operation, thereby achieving better response during abnormal conditions.

Along with the increasing share of non-synchronous power sources, the inertia of power systems is being reduced, which can give rise to frequency containment problems should an outage of a generator or a power infeed happen. Low system inertia is eventually unavoidable, thus power system operators need to be prepared for this condition. This paper addresses the problem of low inertia in the power system from two different perspectives. At a system level, it proposes an operation planning methodology, which utilises a combination of power flow and dynamic simulation for calculation of existing inertia and, if need be, synthetic inertia (SI) to fulfil the security criterion of adequate rate of change of frequency (RoCoF). On a device level, it introduces a new concept for active power controller, which can be applied virtually to any power source with sufficient response time to create synthetic inertia. The methodology is demonstrated for a 24 h planning period, for which it proves to be effective. The performance of SI controller activated in a battery energy storage system (BESS) is positively validated using a real-time digital simulator (RTDS). Both proposals can effectively contribute to facilitating the operation of low inertia power systems.

This paper provides an overview of methods for including Battery Energy Storage Systems (BESS) into electric power grid planning. The general approach to grid planning is the same with and without BESS, but when BESS is included as an alternative, other methods are necessary, which adds significant complexity to the planning problem. Although recent research literature proposes a wide range of methods and models for Cost-Benefit Analysis (CBA) of BESS for grid applications, these are to a little extent applied in practice. For the research-based methods to be suitable for grid planning, they should handle timing of installations as well as sizing and siting of BESS. Moreover, they must capture long-term developments in load and generation. Finally, the CBA methods need realistic modelling of the operational benefits of BESS, taking into account multi-period AC power flow, battery degradation, and utilization for multiple grid services. Keywords: Battery storage , cost-benefit analysis , electric power grid , power system planning © 2020 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.

In order to integrate a proton exchange membrane type (PEM) fuel cell system (FCS) combined with a battery bank to a distribution grid; this paper proposes a local controller based on fuzzy logic. The proposed system provides primary frequency control and local bus voltage support to the local grid. This opposes the passive distributed generation of the present that do not provide auxiliary services, such as back-up power, voltage support and reliability of supply as they operate under constant power factor equal to 1 at all times. During network disturbances, the distributed generations of the present are disconnected until normal operation is reestablished. When the distributed generation penetration is high this may lead to system instability. The microgrid concept is the effective solution for the control and quality improvement of grids with high level of DG penetration. So, the proposed system, also, can be an active controllable microsource of a microgrid in the future that cooperates with other microsources in order to cover the local load demands for active and reactive power either under grid-connected mode or under islanding operating mode. In cases where the distribution grid (working as microgrid) is forced to operate in islanded mode, the hybrid system provides the demanded active and reactive power. The FCS is connected to a weak distribution grid so that the system performance is studied under the worst conditions. The simulation results are obtained using MATLAB software under a severe step load change where the grid is still connected and under islanded operation. In both cases the system presents a good performance.

Few years ago Power Systems consisted mainly of large generation plants supplying distant loads through the utility grids. The last years, though, a number of factors lead this structure to change gradually. Small generators of some MW have been already dispersed (DGs) throughout the transmission grid. The distribution of smaller generation units throughout the distribution system as near as possible to the consumer loads has already begun. The DG, up to now, does not provide auxiliary services such as back-up power, voltage support and reliability of supply and its operation is kept under constant power factor equal to 1 at all times. During network disturbances, the DGs up to the present are disconnected until normal operation is reestablished. When the distributed generation penetration is high this may lead to system instability. Therefore, the DG has to change from passive appendage of primary energy supplier to active sources remaining connected to the grid and offering ancillary services. In some countries legislation changed, so that DG remains connected during disturbances and supports the grid. Under this operating philosophy, DGs must support the grid during local disturbances, as central generation stations support high voltage systems in the transient period. This can be achieved through the control of the DGs electronic interface to the main grid and the energy storage plants. These controllable (centrally or distributed) DGs (

In order to integrate different distributed generations (DGs) into a microgrid connected to a weak distribution grid, this paper proposes local controllers based in fuzzy logic. The integration of the DGs is achieved through the «plug and play» procedure. The understudy microgrid includes an hybrid fuel cell-battery system and a Doubly Fed Induction Generator (DFIG). Through the proposed controllers the DGs provide primary frequency control and local bus voltage support to the local grid in both cases either the microgrid operates in islanded mode or in connected mode when local disturbances occur. Using MATLAB/Simulink software the response of the system is recorded when the microgrid from the connected mode is transferred to the islanded operation and the system presents a good performance.

In order to integrate a proton exchange membrane type (PEM) fuel cell system (FCS) to a distribution system, this paper proposes a local controller for providing primary frequency control and local bus voltage support. The FCS has been designed to operate in the distribution system either this is connected to the mean voltage side or it is disconnected and operated in stand-alone mode. The FCS is connected to a weak distribution grid to study the system performance under local disturbances. The response of the system is recorded under a severe step load change using MATLAB software and proves a good performance of the system.