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Distributed energy resources such as solar photovoltaic, wind and energy storage systems are increasingly being utilised within isolated and grid-connected microgrids. Their integration has prompted the move towards more advanced coordinated control for flexible, efficient and secure operation of microgrid-based power systems. This study presents a new power control method based on a canonical inverse model and implied synthetic inertia (SI), which is implemented on a voltage source converter-based power generator (VSC-PG) for frequency response support. The control method augments a traditional power controller whilst the SI technique is blended with a new switching mechanism which enhances the performance of the VSC-PG when it is utilised with SI provision capability. The switching mechanism acts only when necessary, without contradicting the main frequency regulating sources. For assessment, the above method and SI technique have been designed and modelled for a 630 kVA VSC-PG with DC-link battery bank. The VSC-PG was connected within an isolated/remote microgrid formed by an 11 kV feeder, 1 MVA diesel generator and variable load. The performances of the proposed power controller and SI provider have been tested and analysed using detailed Matlab/Simulink simulations and found to compare favourably with methods published in the literature. [ABSTRACT FROM AUTHOR]

• Layered thermal store was both experimentally and numerically studied. • Layered control resulted in >60 % reduction on pressure drop. • Layered control resulted in uniform exit temperature for a longer period. • Layered store outperforms simple store as it reaches steady-state in 3rd cycle. • 1st and 2nd Law storage cycle efficiencies were analysed. This paper presents a study carried out as part of commissioning and testing of world's first grid-scale 150 kW e Pumped Heat Energy Storage (PHES) demonstration system. The system employs two novel layered packed-bed thermal stores. The present study experimentally investigates one of the stores designated as "hot thermal store", which has an energy storage density of 1072 MJ/m3 and stores heat at 500 °C and 12 bar. The layered store is an enhancement of a normal packed-bed store and offers a higher degree of thermal stratification. Experiments show that layering results in about 64 % reduction in pressure loss along with yielding considerably narrower thermocline. Round-trip efficiency, storage capacity and utilisation were calculated based on 1st Law analysis considering both simple and layered mode operation at nominal design conditions. Two cycle control scenarios were considered: time-based and temperature-based. In the time-based scenario, the store shows nearly similar performance in both modes. However, in temperature-based scenario, layered mode outperforms. During cyclic operation, layered mode outperforms as it reaches steady-state in merely 3rd cycle, without any loss in efficiency, capacity and utilisation; simple mode yields competitive efficiency but capacity and utilisation deteriorate after each successive cycle and steady-state is achieved in 20th cycle. 2nd Law analysis was additionally performed to gain insight into various losses and their impact on the performance. [ABSTRACT FROM AUTHOR]