Fast frequency response provision from commercial demand response, from scheduling to stability in power systems

Abstract

Reduced numbers of online conventional generators, due to increasing shares of renewable energy sources, are increasing the requirement for a fast frequency response capability from reserve providers when a large infeed/outfeed trips. The commercial demand‐side sector, considering its size (MW/MWh) and existing communication and control infrastructure, makes it a potential valuable source of flexibility provision. Supermarket refrigeration systems are considered here as being representative of commercial end‐uses, with individual devices stochastically simulated under different ambient conditions, supermarket occupancy, food categories, and refrigeration performance. An aggregated fleet of supermarket loads are then created to provide a system‐wide reserve response. The all‐island power system of Northern Ireland and Republic of Ireland, with a horizon of 2030, is considered as a representative case study. Three distinct demand‐side frequency control methods, including static, droop, and hybrid control are presented and developed within a stability analysis platform. Year‐long simulation results show a general improvement in the frequency nadir and (maximum) rate of change of frequency when supermarkets are providing fast frequency response services to the grid, with the likelihood of severe transients (frequency nadir <49 Hz) greatly reduced (82% improvement), depending on the FFR control design, and associated speed of response.

A Review of the Energy Storage Systems of Non-Interconnected European Islands

“…FFR is a relatively newer category of services that lies between virtual inertia and FCR [53]. It has applications (in different forms) in Ireland [54], the UK [55] and the Nordics [56], which are systems with lower inertia compared to the continental system of mainland Europe. The main control trigger of FFR is changes in frequency (∆F) instead of the RoCoF (df /dt) and the response time is short, usually a few seconds or even less than a second.…”

Dynamic frequency control strategy for the CSP plant in power systems with low inertia

“…In the inertia response timeframe, the synchronous generators suppress the change of the system frequency by releasing the rotor's kinetic energy or absorbing electric energy. Therefore, the inertia of the system is calculated as Equation ( 7) [28,29]:…”

“…In the inertia response timeframe, the synchronous generators suppress the change of the system frequency by releasing the rotor's kinetic energy or absorbing electric energy. Therefore, the inertia of the system is calculated as Equation () [28, 29]: $$$$\begin{eqnarray} {H}_{{\mathrm{sys}}} &=& \sum_{i \in {N}^{{\mathrm{CON}}}} {H_i^{{\mathrm{CON}}} \cdot P_i^{{\mathrm{CON}}{\mathrm{.max}}} \cdot u_i^{{\mathrm{CON}}}} \nonumber\\ &&+ \sum_{k \in {N}^{{\mathrm{CSP}}}} {H_k^{{\mathrm{CSP}}} \cdot P_k^{{\mathrm{CSP}}{\mathrm{.max}}} \cdot u_k^{{\mathrm{CSP}}}} \end{eqnarray}$$$$where $$H_i^{{\mathrm{CON}}}$$ and $$H_k^{{\mathrm{CSP}}}$$ are the inertia constants of thermal units and CSP plants, respectively; $$u_i^{{\mathrm{CON}}}$$ and $$u_k^{{\mathrm{CSP}}}$$ are the ON/OFF status of thermal units and CSP plants; $$P_i^{{\mathrm{CON}}{\mathrm{.max}}}$$ and $$P_k^{{\mathrm{CSP}}{\mathrm{.max}}}$$ are the maximum capacity of thermal units and CSP plants. The initial RoCoF after contingency is proportional positively and inversely proportional to the power imbalance and the system's inertia [17], which can be calculated as Equation ().…”

Energy Utilization and Conversion in Modern Biomass Conversion Technologies

“…Commercial power generation from biomass for application in energy production, industry, or transport fuel accounts for a smaller but rising portion of modern bio-energy (some 7 EJ/yr in 2000). A total of around 40 GWe of biomassproduced electricity production capabilities (generating 160 TWh annually) and over 200 GW of heat generation capabilities (generating >700 TWh annually) were built across the globe by the expiration of the 19 th century [2]. It is projected that over 18 billion liters of biofuels were generated worldwide in 2016 (mostly ethanol made sugarcane and cereals and maize surpluses, and to a much smaller level bio-fuels produced from the oil seed crop).…”