Overview of current development in electrical energy storage technologies and the application potential in power system operation

Due to the stochastic nature of wind, electric power generated by wind turbines is highly erratic and may affect both the power quality and the planning of power systems. Energy Storage Systems (ESSs) may play an important role in wind power applications by controlling wind power plant output and providing ancillary services to the power system and therefore, enabling an increased penetration of wind power in the system. This article deals with the review of several energy storage technologies for wind power applications. The main objectives of the article are the introduction of the operating principles, as well as the presentation of the main characteristics of energy storage technologies suitable for stationary applications, and the definition and discussion of potential ESS applications in wind power, according to an extensive literature review.

A review of energy storage technologies for wind power applications

The battery energy storage station (BESS) is the current and typical means of smoothing wind- or solar-power generation fluctuations. Such BESS-based hybrid power systems require a suitable control strategy that can effectively regulate power output levels and battery state of charge (SOC). This paper presents the results of a wind/photovoltaic (PV)/BESS hybrid power system simulation analysis undertaken to improve the smoothing performance of wind/PV/BESS hybrid power generation and the effectiveness of battery SOC control. A smoothing control method for reducing wind/PV hybrid output power fluctuations and regulating battery SOC under the typical conditions is proposed. A novel real-time BESS-based power allocation method also is proposed. The effectiveness of these methods was verified using MATLAB/SIMULINK software.

Battery Energy Storage Station (BESS)-Based Smoothing Control of Photovoltaic (PV) and Wind Power Generation Fluctuations

In this work, an overview of the different types of batteries used for large-scale electricity storage is carried out. In particular, the current operational large-scale battery energy storage systems around the world with their applications are identified and a comparison between the different types of batteries, as well as with other types of large-scale energy storage systems, is presented. The analysis has shown that the largest battery energy storage systems use sodium–sulfur batteries, whereas the flow batteries and especially the vanadium redox flow batteries are used for smaller battery energy storage systems. The battery electricity storage systems are mainly used as ancillary services or for supporting the large scale solar and wind integration in the existing power system, by providing grid stabilization, frequency regulation and wind and solar energy smoothing.

A comparative overview of large-scale battery systems for electricity storage

A microgrid (MG) is a local entity that consists of distributed energy resources (DERs) to achieve local power reliability and sustainable energy utilization. The MG concept or renewable energy technologies integrated with energy storage systems (ESS) have gained increasing interest and popularity because it can store energy at off-peak hours and supply energy at peak hours. However, existing ESS technology faces challenges in storing energy due to various issues, such as charging/discharging, safety, reliability, size, cost, life cycle, and overall management. Thus, an advanced ESS is required with regard to capacity, protection, control interface, energy management, and characteristics to enhance the performance of ESS in MG applications. This paper comprehensively reviews the types of ESS technologies, ESS structures along with their configurations, classifications, features, energy conversion, and evaluation process. Moreover, details on the advantages and disadvantages of ESS in MG applications have been analyzed based on the process of energy formations, material selection, power transfer mechanism, capacity, efficiency, and cycle period. Existing reviews critically demonstrate the current technologies for ESS in MG applications. However, the optimum management of ESSs for efficient MG operation remains a challenge in modern power system networks. This review also highlights the key factors, issues, and challenges with possible recommendations for the further development of ESS in future MG applications. All the highlighted insights of this review significantly contribute to the increasing effort toward the development of a cost-effective and efficient ESS model with a prolonged life cycle for sustainable MG implementation.

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Review of Energy Storage System Technologies in Microgrid Applications: Issues and Challenges

Renewable energy sources such as wind turbine and photovoltaic power generators may make the power grid unstable due to their output fluctuations. Battery energy storage systems (BESSs) are being considered as a countermeasure for this issue. A modular multilevel cascade converter (MMCC) is expected as a power conversion circuit for BESSs because each bridge cell can control the state of charge of a battery unit, independent of that of another one, and the harmonic current generated is low enough to eliminate the ac filter, normally installed on conventional two-level converters, from the MMCC. This paper describes the development of a real-scale (500 kW) single-star-bridge-cell-based MMCC for BESSs and reports successful test results obtained from a downscaled grid model and a 6.6-kV real-scale distribution line.

Development of a 500-kW Modular Multilevel Cascade Converter for Battery Energy Storage Systems

Wind turbines (WTs) are considered to be one of effective approach to solve global warming and energy issues. However, the output of WTs depends on the weather conditions and the natural environment, which cause large fluctuations in the output power, leading to insufficient of frequency adjustment capacity of the power grid. Several methods have been examined to compensate for such large fluctuations using batteries. In this paper, we describe the development of the world's largest constant output stabilization system using 34 MW sodium sulfur (NAS) batteries for a 51 MW wind farm at Futamata in the Tohoku district of Japan, as well as our field experiences indicating excellent operating performance.

Development and field experiences of stabilization system using 34MW NAS batteries for a 51MW wind farm

A power control device includes an electric power storage device connected across a power supply line for a load and including at least one electric double layer capacitor (EDLC) bank and a secondary battery combined with the EDLC bank, the EDLC bank including a plurality of parallel-connected rows of EDLC unit cells, each of the rows including a plurality of series-connected EDLC unit cells, and a control device controlling the electric power storage device so that when an input power to the electric power storage device is interrupted, the EDLC bank supplies electric power to the load for an initial period of the power interrupt and subsequently, the secondary battery supplies electric power to the load.

Power control device with electric double layer capacitor unit cells

A DC component contained in an output of a voltage source self-commutated converter causes a converter transformer to be DC-magnetized, in the worst case causing an overcurrent due to saturation. We experienced the DC-magnetization of the converter transformer of a 50 MVA self-commutated SVC installed in the Shinshinano Substation of Tokyo Electric Power Company when system disturbances occurred by energizing of an adjacent large capacity transformer. After analysing the problem, a novel DC magnetization prevention control was developed that makes a fast flux correction according to the voltage DC component detected in the converter output. This method was applied to the 50 MVA self-commutated SVC and produced satisfactory operation results.

A new control method preventing transformer DC magnetization for voltage source self-commutated converters

Wind Turbine Generator Systems (WTGSs) are considered to be one of effective approach to solve global warming and energy issues. However, the stability of the output power generated from WTGSs depends on the weather conditions and the natural environment, and any instability in the power causes frequency fluctuations in the power grid. Several methods have been examined to stabilize such fluctuations using batteries. In this paper, we describe the development of an inverter using sodium sulfur (NAS) batteries to stabilize the power from a wind farm and our field experiences indicating excellent operating performance. This system is the world's largest constant-output stabilization system using 34 MW NAS batteries for a 51 MW wind farm at Futamata in the Tohoku district of Japan.

Noriko Kawakami

Papers

Development of a 500-kW Modular Multilevel Cascade Converter for Battery Energy Storage Systems

Development and field experiences of stabilization system using 34MW NAS batteries for a 51MW wind farm

Power control device with electric double layer capacitor unit cells

A new control method preventing transformer DC magnetization for voltage source self-commutated converters

Development and field experiences of NAS battery inverter for power stabilization of a 51 MW wind farm