This paper presents a novel fast frequency and voltage regulation method for battery energy storage system (BESS) based on the amplitude-phase-locked-loop (APLL). In the proposed method, the primary frequency regulation and inertia emulating control are designed based on grid frequency deviation (<inline-formula> <tex-math notation="LaTeX">${\Delta }f$ </tex-math></inline-formula>) and its differential <inline-formula> <tex-math notation="LaTeX">$(df/dt)$ </tex-math></inline-formula> signals detected by APLL, avoiding complicated and sensitive differential operation to get better dynamic support performance. Moreover, unlike the traditional voltage control only using grid voltage deviation (<inline-formula> <tex-math notation="LaTeX">${\Delta }V$ </tex-math></inline-formula>), the proposed method also uses the voltage differential control (<inline-formula> <tex-math notation="LaTeX">$dV/dt$ </tex-math></inline-formula>-control) to improve dynamic performance of traditional voltage control and behaviors of grid voltage based on the <inline-formula> <tex-math notation="LaTeX">$dV/dt$ </tex-math></inline-formula> signal from APLL. Finally, simulations and experiments are implemented to validate the effectiveness of the proposed APLL-based BESS on improving the dynamic behaviors of grid frequency and voltage.

Fast Grid Frequency and Voltage Control of Battery Energy Storage System Based on the Amplitude-Phase-Locked-Loop

Integrated power systems are popular in the shipbuilding industry. DC shipboard microgrids (dc-SMGs) have many advantages compared with ac ones in terms of system efficiency, operation flexibility, component size, and fault protection performance. Being in the exploring stage, dc-SMGs have several potential configurations with different system architectures and voltage levels. In a dc-SMG, functional blocks integrated include power generation modules (PGMs), propulsion system, high power loads, and pulsed loads specifically in naval ships. In modern ships, the PGMs include not only generators and fuel cells but also energy storage systems (ESSs), which cooperate with generators to improve the overall efficiency and reliability. High power electric converters are vital interfaces between the functional blocks and the dc distribution system. Rectifiers for generators take the tasks of dc bus voltage regulation and power sharing. Inverters for propulsion motors are responsible for the motor drive in different operating conditions. Bidirectional dc&#x002F;dc converters for ESSs are used to provide supply-demand balance and voltage fluctuation mitigation. This article makes a comprehensive review of power architecture, functional blocks including electrical machines and energy storage, as well as power converters in dc shipboard power systems. 

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A Review of DC Shipboard Microgrids—Part I: Power Architectures, Energy Storage, and Power Converters

Accurate inertia estimates and forecasts are crucial to support the system operation in future low-inertia power systems. A large literature on inertia estimation methods is available. This paper aims to provide an overview and classification of inertia estimation methods. The classification considers the time horizon the methods are applicable to, i.e., offline post mortem, online real time and forecasting methods, and the scope of the inertia estimation, e.g., system-wide, regional, generation, demand, individual resource. Shortcomings of the existing inertia estimation methods have been identified and suggestions for future work have been made.

Challenges and opportunities of inertia estimation and forecasting in low-inertia power systems

Accurate inertia estimates and forecasts are crucial to support the system operation in future low-inertia power systems. A large literature on inertia estimation methods is available. This paper aims to provide an overview and classification of inertia estimation methods. The classification considers the time horizon the methods are applicable to, i.e., offline post mortem, online real time and forecasting methods, and the scope of the inertia estimation, e.g., system-wide, regional, generation, demand, individual resource. The framework presented in this paper facilitates objective comparisons of the performance of newly developed or improved inertia estimation methods with the state-of-the-art methods in their respective time horizon and with their respective scope. Moreover, shortcomings of the existing inertia estimation methods have been identified and suggestions for future work have been made.

Addressing frequency control challenges in future low-inertia power systems: a Great Britain perspective

Electric power systems foresee challenges in stability due to the high penetration of power electronics interfaced renewable energy sources. The value of energy storage systems (ESS) to provide fast frequency response has been more and more recognized. Although the development of energy storage technologies has made ESSs technically feasible to be integrated in larger scale with required performance, the policies, grid codes and economic issues are still presenting barriers for wider application and investment. Recent years, a few regions and countries have designed new services to meet the upcoming grid challenges. A number of grid-scale ESS projects are also implemented aiming to trial performance, demonstrate values, and gain experience. This paper makes a review on the above mentioned aspects, including the emerging frequency regulation services, updated grid codes and grid-scale ESS projects. Some key technical issues are also discussed and prospects are outlined.

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Alan Collinson

Papers

Fast Frequency Response From Energy Storage Systems—A Review of Grid Standards, Projects and Technical Issues