The science and technology of ultracapacitors are reviewed for a number of electrode materials, including carbon, mixed metal oxides, and conducting polymers. More work has been done using microporous carbons than with the other materials and most of the commercially available devices use carbon electrodes and an organic electrolytes. The energy density of these devices is 3¯5 Wh/kg with a power density of 300¯500 W/kg for high efficiency (90¯95%) charge/discharges. Projections of future developments using carbon indicate that energy densities of 10 Wh/kg or higher are likely with power densities of 1¯2 kW/kg. A key problem in the fabrication of these advanced devices is the bonding of the thin electrodes to a current collector such the contact resistance is less than 0.1 cm2. Special attention is given in the paper to comparing the power density characteristics of ultracapacitors and batteries. The comparisons should be made at the same charge/discharge efficiency.

Ultracapacitors: Why, How, and Where is the Technology

Large-scale deployment of intermittent renewable energy (namely wind energy and solar PV) may entail new challenges in power systems and more volatility in power prices in liberalized electricity markets. Energy storage can diminish this imbalance, relieving the grid congestion, and promoting distributed generation. The economic implications of grid-scale electrical energy storage technologies are however obscure for the experts, power grid operators, regulators, and power producers. A meticulous techno-economic or cost-benefit analysis of electricity storage systems requires consistent, updated cost data and a holistic cost analysis framework. To this end, this study critically examines the existing literature in the analysis of life cycle costs of utility-scale electricity storage systems, providing an updated database for the cost elements (capital costs, operational and maintenance costs, and replacement costs). Moreover, life cycle costs and levelized cost of electricity delivered by electrical energy storage is analyzed, employing Monte Carlo method to consider uncertainties. The examined energy storage technologies include pumped hydropower storage, compressed air energy storage (CAES), flywheel, electrochemical batteries (e.g. lead–acid, NaS, Li-ion, and Ni–Cd), flow batteries (e.g. vanadium-redox), superconducting magnetic energy storage, supercapacitors, and hydrogen energy storage (power to gas technologies). The results illustrate the economy of different storage systems for three main applications: bulk energy storage, T&D support services, and frequency regulation.

Electrical energy storage systems: A comparative life cycle cost analysis

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

Fault detection, isolation, and reconfiguration (FDIR) is an important and challenging problem in many engineering applications and continues to be an active area of research in the control community. This paper presents a survey of the various model-based FDIR methods developed in the last decade. In the paper, the FDIR problem is divided into the fault detection and isolation (FDI) step, and the controller reconfiguration step. For FDI, we discuss various model-based techniques to generate residuals that are robust to noise, unknown disturbance, and model uncertainties, as well as various statistical techniques of testing the residuals for abrupt changes (or faults). We then discuss various techniques of implementing reconfigurable control strategy in response to faults.

A Survey of Fault Detection, Isolation, and Reconfiguration Methods

(1990). ENERGY FUNCTION ANALYSIS FOR POWER SYSTEM STABILITY. Electric Machines & Power Systems: Vol. 18, No. 2, pp. 209-210.

Energy function analysis for power system stability

In this paper, iterative linear matrix inequalities (ILMI) algorithm based design of decentralized controller for load frequency control (LFC) is proposed. The ILMI algorithm is used to tune the control parameters of the proportional-integral-derivative (PID) controller subject to H∞ constraints in terms of ILMI. Hence, the control design is called IPIDH∞ controller. The proposed controller is tested on a two-area interconnected power system considering reheat type turbine in both area with different load scenarios. The results of the proposed controller are compared with the H∞-controller. From the simulation results, the proposed controller is superior to H∞-controller.

Iterative linear matrix inequality algorithm based decentralized controller for load frequency control of two-area thermal power systems

Available Transfer Capability is determinental in facilitating operation of power system economically, reliably and securely. Advancements in the power generation techniques and shift in generation methodologies from centralized to disbursed/distributed generation with increased emphasis on renewable sources has complicated the assessment and enhancement of ATC. In this paper a multi-stage operational strategy for enhancement and assessment of ATC in the presence of renewable sources of generation and FACTS devices is presented. The developed method is implemented on Modified IEEE 24 bus test system.

Optimal Strategy for ATC Enhancement and Assessment in presence of FACTS devices and Renewable Generation

A Harris Hawks Optimization (HHO)tuned dual interval type-2 fuzzy lead–lag (Dual-IT2FLL) based unified power flow controller (UPFC) is proposed to minimize oscillations in single and multimachine power systems. The proposed damping controller coordinates between the modulation index (MI) and phase angle of series and shunt converters of UPFC simultaneously and is designed using speed deviation, a remote input signal for stability improvement. The performance of the proposed controller is verified through nonlinear time and frequency domain simulations under different operating conditions. The graphical simulations and validations using OPAL-RT OP5600 are presented to access the stability performance. Comparison based on different performance indices (PIs), like mean, standard deviation, overshoots and settling time are also considered to prove the better performance of the proposed HHO tuned dual-IT2FLL based UPFC over others under different operating conditions.

A robust dual interval type-2 fuzzy lead–lag based UPFC for stability enhancement using Harris Hawks Optimization

Reduced order modelling of complex autonomous microgrid system is crucial to its small signal modelling and stability concerns. To reduce the storage requirements and computational time, the order ...

https://www.tandfonline.com/doi/pdf/10.1080/00051144.2019.1682867

PSO Based reduced order modelling of autonomous AC microgrid considering state perturbation

This paper presents a protection scheme for wind power based Permanent Magnet Synchronous Generator (PMSG). To protect the connected equipment in the generation system, over-current and differential frequency relays, are used. Massive current flow and frequency change in the power line affect the equipments. Over-current relay and differential frequency relay are used to solve these problems. A study to protect this circuit topology is carried out, performing the simulation on MATLAB®. The proposed scheme protects the power system from over-current, and frequency variation. Meanwhile, the attention is paid that the incoming and outgoing frequencies difference should be maintained to zero. During the simulation, standard values of generator speed, wind speed, and pitch angle are used. The proposed scheme is found suitable for over current and heavy frequency variation with better operating time.

Soumya R. Mohanty

Papers

Iterative linear matrix inequality algorithm based decentralized controller for load frequency control of two-area thermal power systems

Optimal Strategy for ATC Enhancement and Assessment in presence of FACTS devices and Renewable Generation

A robust dual interval type-2 fuzzy lead–lag based UPFC for stability enhancement using Harris Hawks Optimization

PSO Based reduced order modelling of autonomous AC microgrid considering state perturbation

Wind power generation by PMSG and fault protection using over-current and differential frequency relay