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33 pages, 16646 KiB

Open AccessArticle

Triple Phase Shift Control of Wireless Charging DAB LCC Resonant Converter for Unity Power Factor Operation with Optimized Rectifier AC Load Resistance

by Yanni Cheong, Shuyu Cao, Ramasamy Thaiyal Naayagi and Szesing Lee

Appl. Sci. 2022, 12(22), 11871; https://doi.org/10.3390/app122211871 - 21 Nov 2022

Cited by 6 | Viewed by 2915

Abstract

This paper presents a new triple phase shift (TPS) closed-loop control scheme of a dual active bridge (DAB) LCC resonant DC/DC converter to improve wireless charging power transfer efficiency. The primary side inverter phase shift angle regulates the battery charging current/voltage. The secondary [...] Read more.

This paper presents a new triple phase shift (TPS) closed-loop control scheme of a dual active bridge (DAB) LCC resonant DC/DC converter to improve wireless charging power transfer efficiency. The primary side inverter phase shift angle regulates the battery charging current/voltage. The secondary side rectifier phase shift angle regulates the rectifier AC load resistance to match its optimized setting. The inverter-to-rectifier phase shift angle is set to achieve unity power factor operation of the DAB rectifier and inverter. The mathematical formulation of the TPS shift control is given for each phase shift angle. The analytical calculation, circuit simulation, and experimental test are carried out in a power scaled-down DAB LCC resonant wireless charging converter laboratory hardware setup to validate the proposed TPS close-loop control scheme. The PLECS circuit simulation shows that DAB LCC resonant SiC MOSFET operates at zero-voltage-switching (ZVS) with a unity power factor in emulated constant current (CC) mode battery charging. In constant voltage (CV) mode operation, one inverter/rectifier Leg does not operate at ZVS switching when Sic MOSFET is switched on near zero current. The experimental results show that the efficiency is greatly improved for CV mode charging with large DC load resistance connected if rectifier AC load resistance matching control is enabled. The measured efficiency matches well with the analytical calculation. The estimated efficiency improvement will be much more significant for EV applications in the kW power range with greater winding loss. The challenges and possible solutions to implement TPS PWM modulation in two separate inverter and rectifier control hardware are explained for future TPS control algorithm development in practical wireless charging products. Full article

(This article belongs to the Special Issue Electric Power Applications)

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31 pages, 6351 KiB

Open AccessArticle

Frequency Stability Analysis of a Low Inertia Power System with Interactions among Power Electronics Interfaced Generators with Frequency Response Capabilities

by Lucio Radaelli and Sergio Martinez

Appl. Sci. 2022, 12(21), 11126; https://doi.org/10.3390/app122111126 - 2 Nov 2022

Cited by 6 | Viewed by 2454

Abstract

One of the main actions required to face and limit global warming is the substitution of conventional fossil-fueled electrical generators with renewable ones. Thus, it becomes fundamental to create non-dispatchable renewable generators able to provide services for power system stabilization that nowadays are [...] Read more.

One of the main actions required to face and limit global warming is the substitution of conventional fossil-fueled electrical generators with renewable ones. Thus, it becomes fundamental to create non-dispatchable renewable generators able to provide services for power system stabilization that nowadays are delivered by conventional ones. Particularly, renewable generators are usually connected to the electrical power system through power electronic converters lacking natural responses to frequency variations. This challenges conventional frequency control methods that are based on synchronous generators’ capabilities, particularly in systems with high levels of non-synchronous generation. Solutions based on advanced controls that allow renewable generators to participate in frequency control are the subject of current research efforts worldwide. This paper contributes to these efforts by studying the benefits of introducing Power Reserve Control in photovoltaic generators and Extended Optimal Power Point Tracking control in wind generators to provide frequency control in low inertia power systems and the interactions between them. The tests and the simulations, prove that these kinds of controls help in stabilizing the system frequency thanks to the cooperative action of both types of renewable generators. Full article

(This article belongs to the Special Issue Electric Power Applications)

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20 pages, 3355 KiB

Open AccessFeature PaperArticle

Optimal Selection of the Diesel Generators Supplying a Ship Electric Power System

by Panayiotis Michalopoulos, George J. Tsekouras, Fotios D. Kanellos and John M. Prousalidis

Appl. Sci. 2022, 12(20), 10463; https://doi.org/10.3390/app122010463 - 17 Oct 2022

Cited by 5 | Viewed by 2730

Abstract

It is very common for ships to have electric power systems comprised of generators of the same type. This uniformity allows for easier and lower-cost maintenance. The classic way to select these generators is primarily by power and secondarily by dimensions and acquisition [...] Read more.

It is very common for ships to have electric power systems comprised of generators of the same type. This uniformity allows for easier and lower-cost maintenance. The classic way to select these generators is primarily by power and secondarily by dimensions and acquisition cost. In this paper, a more comprehensive way to select them, using improved cost indicators, is proposed. These take into account many factors that have a significant impact in the life-cycle cost of the equipment. A realistic and detailed profile of the ship’s electric load spanning a full year of her operation is also developed to allow for a solution that is tailor-made to a specific case. The method used is highly iterative. All combinations of genset quantities and capacities are individually considered to populate a power plant, taking into account the existing redundancy requirements. For each of these and for every time interval in the load profile, the engine consumption is Lagrange-optimized to determine the most efficient combination to run the generators and the resulting cost. The operating cost throughout the year is thus derived. In this way, the method can lead to optimal results as large data sets regarding ship operation and her power system’s technical characteristics can be utilized. This intense calculation process is greatly accelerated using memorization techniques. The reliability cost of the current power plant is also considered along with other cost factors, such as flat annual cost, maintenance, and personnel. The acquisition and installation cost are also included, after being distributed in annuities for various durations and interest rates. The results provide valuable insight into the total cost from every aspect and present the optimum generator selection for minimal expenditure and maximum return of investment. This methodology may be used to enhance the current power-plant design processes and provide investors with more feasible alternatives, as it takes into consideration a multitude of technical and operational characteristics of the examined ship power system. Full article

(This article belongs to the Special Issue Electric Power Applications)

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18 pages, 1780 KiB

Open AccessArticle

Fault Diagnosis Method of Intelligent Substation Protection System Based on Gradient Boosting Decision Tree

by Wei Ding, Qing Chen, Yuzhan Dong and Ning Shao

Appl. Sci. 2022, 12(18), 8989; https://doi.org/10.3390/app12188989 - 7 Sep 2022

Cited by 10 | Viewed by 1836

Abstract

In order to improve the efficiency of the devices’ fault diagnosis of the protection systems of intelligent substation, a fault diagnosis method based on a gradient boosting decision tree (GBDT) was proposed. Using the integrated alarm information, the device self-checking information, the link [...] Read more.

In order to improve the efficiency of the devices’ fault diagnosis of the protection systems of intelligent substation, a fault diagnosis method based on a gradient boosting decision tree (GBDT) was proposed. Using the integrated alarm information, the device self-checking information, the link information of generic object-oriented substation event (GOOSE) and sampled value (SV) and the sampling value information generated during the fault of the protection system, the fault feature information set is constructed. According to different fault characteristics, the protection system faults are classified into simple faults and complex faults to improve the diagnosis efficiency. Using GBDT training rules, a fault diagnosis model of protection system based on GBDT is established and fault diagnosis steps are given. This study takes a 110 kV intelligent substation in southern China as an example, to verify the effectiveness and accuracy of the proposed fault diagnosis method, and compared it with the existing methods in terms of the accuracy. The diagnostic accuracy in the case of false alarms and the case of multiple faults are verified. The results show that the method can meet the practical engineering application. Full article

(This article belongs to the Special Issue Electric Power Applications)

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13 pages, 11878 KiB

Open AccessArticle

Research on the Distribution Characteristics of Transformer Axial Vibration under Short-Circuit Conditions Considering Damping Parameters

by Shuguo Gao, Lu Sun, Yuan Tian and Hongliang Liu

Appl. Sci. 2022, 12(17), 8443; https://doi.org/10.3390/app12178443 - 24 Aug 2022

Cited by 5 | Viewed by 1459

Abstract

The existing research on the distribution characteristics of displacement and acceleration of the transformer axial vibration under short-circuit conditions is based on ignoring the damping parameters. An accurate description of the axial distribution characteristics of the windings, especially for the axial vibration of [...] Read more.

The existing research on the distribution characteristics of displacement and acceleration of the transformer axial vibration under short-circuit conditions is based on ignoring the damping parameters. An accurate description of the axial distribution characteristics of the windings, especially for the axial vibration of the winding under short-circuit conditions, has a poor effect. In this paper, the damping, stiffness, and mass parameters between windings are comprehensively considered, and the classical “mass-spring-damping” axial vibration mathematical model of transformer windings is established. After solving, the natural frequency, main mode shape, displacement, and acceleration of each wire cake of the multi-degree-of-freedom (multi-DOF) vibration system were quickly obtained. The relationship between the axial displacement and acceleration of the wire cake and the axial deformation of the transformer winding was discussed, and the transformer winding axis was summarized as well as characteristics of the vibration distribution. Full article

(This article belongs to the Special Issue Electric Power Applications)

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16 pages, 3351 KiB

Open AccessArticle

Power Factor Correction Application Based on Independent Double-Boost Interleaved Converter (IDBIC)

by Norbert Csaba Szekely, Sorin Ionut Salcu, Vasile Mihai Suciu, Lucian Nicolae Pintilie, Gheorghe Ioan Fasola and Petre Dorel Teodosescu

Appl. Sci. 2022, 12(14), 7209; https://doi.org/10.3390/app12147209 - 18 Jul 2022

Cited by 4 | Viewed by 2246

Abstract

In this paper, a Power Factor Correction (PFC) application, based on the novel power stage topology named Independent Double-Boost Interleaved Converter (IDBIC), has been analyzed. The novelty of the proposed PFC rectifier is based on the sum of capabilities, such as supplying three [...] Read more.

In this paper, a Power Factor Correction (PFC) application, based on the novel power stage topology named Independent Double-Boost Interleaved Converter (IDBIC), has been analyzed. The novelty of the proposed PFC rectifier is based on the sum of capabilities, such as supplying three independent output voltage levels with interleaved operation at the input and high voltage gain. The hardware used within this application consists of an AC input L-C-L filter, a single-phase bridge rectifier, the IDBIC power stage, output capacitors group and a group of variable high-power rheostats (resistors) group as DC load. The main purpose of the carried study was to highlight the advantages and disadvantages of the novel power stage topology in the context of a green and modern AC to DC conversion solution. Nowadays, a high level of the efficiency and power factor have become a mandatory feature for the AC to DC conversion solutions to satisfy the international electrical standards. Thus, considering the modern electrical standards and recommendations, the current study tries to better depict the working steps and principles of the modern power stage topology within an AC to DC conversion application. The behavior of the considered power stage described in different detailed working steps (such as the Discontinuous Conduction Mode and Continuous Conduction Mode) may help understand how the energy conversions process of AC to DC becomes more efficient. The high output voltage gain of the considered power stage is the key feature in the Power Factor Correction process. With such a feature, the AC to DC conversion solution/application can also operate at lower input AC voltages (such as 90 [V] and 110 [V]). The proposed solution can be successfully used in the electric vehicle (automotive field) and high-power electrical traction (e.g., trains, high power electrical machines and drives). The same solution can also be used successfully in fast battery charging applications and chemical electrolysis processes. Full article

(This article belongs to the Special Issue Electric Power Applications)

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15 pages, 2685 KiB

Open AccessArticle

Energy Efficiency Improvement of Diesel–Electric Trains Using Solar Energy: A Feasibility Study

by Ahmad Fayad, Hussein Ibrahim, Adrian Ilinca, Sasan Sattarpanah Karganroudi and Mohamad Issa

Appl. Sci. 2022, 12(12), 5869; https://doi.org/10.3390/app12125869 - 9 Jun 2022

Cited by 2 | Viewed by 2992

Abstract

Nowadays, productivity challenges in modern manufacturing systems have been the driving force in generating energy-efficient technologies in every industry, including diesel–electric locomotives. The diesel–electric locomotive is one of the most widely used methods in rail transportation, especially in North America. More precisely, the [...] Read more.

Nowadays, productivity challenges in modern manufacturing systems have been the driving force in generating energy-efficient technologies in every industry, including diesel–electric locomotives. The diesel–electric locomotive is one of the most widely used methods in rail transportation, especially in North America. More precisely, the evolution of the electric transmission has allowed the locomotive’s effective tractive effort to increase its diesel engine horsepower. In this paper, we study a new way to improve the energy efficiency of diesel–electric trains using photovoltaic solar panels. This solution is suitable for reducing greenhouse gas emissions of the diesel–electric locomotive system, particularly in cold climates. We explore the amount of energy produced by the PV solar panels and compare it with that produced by the auxiliary diesel-generator during a train’s journey. This comparison clarifies the actual percentage of energy that solar panels can cover. Thus, this paper presents a validation of feasibility and profitability as a function of the train’s specific operating conditions and the meteorological data associated with their routes. Based on the results, the minimum annual fuel reduction of auxiliary generators allowed using PV solar panels is above 50% in all cases and wagon classes, proving this solution’s feasibility. Regarding the comparison, case 3 (Sept-Îles to Schefferville) and case 4 (Luxor to Aswan) are the best, with over 100% of the energy provided by PV solar panels in all the wagons’ classes. The payback period ranges from 2.5 years to 9.1 years, while the CO₂ emission reduction’s revenues range from $460 to $998 per year/wagon. Full article

(This article belongs to the Special Issue Electric Power Applications)

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13 pages, 1262 KiB

Open AccessArticle

Optimal Management of Reactive Power Considering Voltage and Location of Control Devices Using Artificial Bee Algorithm

by Hassan Shokouhandeh, Sohaib Latif, Sadaf Irshad, Mehrdad Ahmadi Kamarposhti, Ilhami Colak and Kei Eguchi

Appl. Sci. 2022, 12(1), 27; https://doi.org/10.3390/app12010027 - 21 Dec 2021

Cited by 34 | Viewed by 2686

Abstract

Reactive power compensation is one of the practical tools that can be used to improve power systems and reduce costs. These benefits are achieved when the compensators are installed in a suitable place with optimal capacity. This study solves the issues of optimal [...] Read more.

Reactive power compensation is one of the practical tools that can be used to improve power systems and reduce costs. These benefits are achieved when the compensators are installed in a suitable place with optimal capacity. This study solves the issues of optimal supply and the purchase of reactive power in the IEEE 30-bus power system, especially when considering voltage stability and reducing total generation and operational costs, including generation costs, reserves, and the installation of reactive power control devices. The modified version of the artificial bee colony (MABC) algorithm is proposed to solve optimization problems and its results are compared with the artificial bee colony (ABC) algorithm, the particle swarm optimization (PSO) algorithm and the genetic algorithm (GA). The simulation results showed that the minimum losses in the power system requires further costs for reactive power compensation. Also, optimization results proved that the proposed MABC algorithm has a lower active power loss, reactive power costs, a better voltage profile and greater stability than the other three algorithms. Full article

(This article belongs to the Special Issue Electric Power Applications)

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19 pages, 4919 KiB

Open AccessFeature PaperArticle

Performance Analysis of Direct Torque Controllers in Five-Phase Electrical Drives

by Mario Bermúdez, Federico Barrero, Cristina Martín and Manuel Perales

Appl. Sci. 2021, 11(24), 11964; https://doi.org/10.3390/app112411964 - 16 Dec 2021

Cited by 13 | Viewed by 2500

Abstract

The industrial application of electric machines has grown in the last decades, thanks to the development of microprocessors and power converters, which have permitted their use as variable-speed drives. Although three-phase machines are the common trend, the interest of the research community has [...] Read more.

The industrial application of electric machines has grown in the last decades, thanks to the development of microprocessors and power converters, which have permitted their use as variable-speed drives. Although three-phase machines are the common trend, the interest of the research community has recently focused on machines with more than three phases, known as multiphase machines. The principal reason lies in the exploitation of their advantages in terms of reliability, i.e., post-fault operating capability. Additionally, multiphase machines provide a better current distribution among phases, and lower current harmonic production in the power converter, than conventional three-phase machines. However, multiphase drive applications require the development of complex controllers to regulate the torque (or speed) and flux of the machine. In this regard, direct torque controllers have appeared as a viable alternative due to their easy formulation and high flexibility to incorporate control objectives. However, these controllers face some peculiarities and limitations in their use that require attention. This work aims to tackle direct torque control as a viable alternative for the regulation of multiphase drives. Special attention will be paid to the development of the control technique and the expected benefits and limitations in the obtained results. Case examples based on symmetrical five-phase induction machines with distributed windings in the motoring mode of operation will be used to this end. Full article

(This article belongs to the Special Issue Electric Power Applications)

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20 pages, 1768 KiB

Open AccessArticle

Maintenance Management of a Transmission Substation with Optimization

by Peter Kitak, Lovro Belak, Jože Pihler and Janez Ribič

Appl. Sci. 2021, 11(24), 11806; https://doi.org/10.3390/app112411806 - 12 Dec 2021

Cited by 4 | Viewed by 3456

Abstract

The paper deals with the reliability-centered maintenance (RCM) of a transmission substation. The process of the planning and actual performance of maintenance was carried out using an optimization algorithm. This maintenance procedure represents the maintenance management and included reliability of the power system [...] Read more.

The paper deals with the reliability-centered maintenance (RCM) of a transmission substation. The process of the planning and actual performance of maintenance was carried out using an optimization algorithm. This maintenance procedure represents the maintenance management and included reliability of the power system operation, maintenance costs, and associated risks. The originality of the paper lies in the integrated treatment of all maintenance processes that are included in the pre-processing and used in the optimization process for reliability-centered maintenance. The optimization algorithm of transmission substation maintenance was tested in practice on the equipment and components of an existing 400/110–220/110 kV substation in the Slovenian electricity transmission system. A comparison analysis was also carried out of the past time-based maintenance (TBM) and the new reliability-centered maintenance (RCM), on the basis of the optimization algorithm. Full article

(This article belongs to the Special Issue Electric Power Applications)

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15 pages, 1420 KiB

Open AccessArticle

Power-Based Concept for Current Injection by Inverter-Interfaced Distributed Generations during Transmission-Network Faults

by Boštjan Polajžer, Bojan Grčar, Jernej Černelič and Jožef Ritonja

Appl. Sci. 2021, 11(21), 10437; https://doi.org/10.3390/app112110437 - 6 Nov 2021

Cited by 1 | Viewed by 1807

Abstract

This paper analyzes the influence of inverter-interfaced distributed generations’ (IIDGs) response during transmission network faults. The simplest and safest solution is to switch IIDGs off during network faults without impacting the network voltages. A more elaborate and efficient concept, required by national grid [...] Read more.

This paper analyzes the influence of inverter-interfaced distributed generations’ (IIDGs) response during transmission network faults. The simplest and safest solution is to switch IIDGs off during network faults without impacting the network voltages. A more elaborate and efficient concept, required by national grid codes, is based on controlling the IIDGs’ currents, involving positive- and negative-sequence voltage measured at the connection point. In this way the magnitude and phase of the injected currents can be adjusted, although the generated power will depend on the actual line voltages at the connection point. Therefore, an improved concept is proposed to adjust IIDGs’ fault current injection through the required active and reactive power, employing the same voltage characteristics. The proposed, i.e., power-based concept, is more definite than the current-based one, since the required power will always be generated. The discussed concepts for the fault current injection by IIDGs were tested in different 110-kV networks with loop and radial topologies, and for different short-circuit capabilities of the aggregated network supply. Based on extensive numerical calculations, the power-based concept during transmission networks faults generates more reactive power compared to the current-based concept. However, the voltage support by IIDGs during transmission networks faults, regardless of the concept being used, is influenced mainly by the short-circuit capability of the aggregated network supply. As regards distance protection operation, it is influenced additionally by the network topology, i.e., in radial network topology, the remote relay’s operation can be delayed due to a largely seen impedance. Full article

(This article belongs to the Special Issue Electric Power Applications)

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43 pages, 5996 KiB

Open AccessArticle

An Adaptive and Scalable Protection Coordination System of Overcurrent Relays in Distributed-Generator-Integrated Distribution Networks

by Duong Minh Bui, Phuc Duy Le, Thanh Phuong Nguyen and Hung Nguyen

Appl. Sci. 2021, 11(18), 8454; https://doi.org/10.3390/app11188454 - 12 Sep 2021

Cited by 7 | Viewed by 3116

Abstract

Integration of distributed generators (DGs) into a distribution network (DN) can cause coordination challenges of overcurrent relays (OCRs) because of different fault-current contributions of DGs as well as the directional change in fault currents. Therefore, the OCRs should be properly coordinated to maintain [...] Read more.

Integration of distributed generators (DGs) into a distribution network (DN) can cause coordination challenges of overcurrent relays (OCRs) because of different fault-current contributions of DGs as well as the directional change in fault currents. Therefore, the OCRs should be properly coordinated to maintain their adaptability and scalability to protect the DG-integrated distribution network. In this study, an adaptive and scalable protection coordination (ASPC) approach has been developed for the OCRs in a DG-contained distribution network based on two implementation stages. At the first stage, the reliability improvement of fault-current calculation results is performed by determining the min-max confidence interval of fault current for each different fault type, which is the basis for properly selecting tripping and pick-up thresholds of definite-time and inverse-time OC functions in the same OCR. At the second stage, optimization algorithms are used for calculating protection-curve coefficients and Time-Dial Setting (TDS) multiplier for the inverse-time OC functions in the OCR. A real 22 kV DG-integrated distribution network which is simulated by ETAP software is considered a reliable test-bed to validate the proposed ASPC system of OCRs in the multiple-DG-contained distribution network. In addition, the coordination results of OCRs can be obtained by three common optimization algorithms, Particle Swarm Optimization (PSO), Gravitational Search Algorithm (GSA), and Genetic Algorithm (GA). These relay coordination results have shown an effective protection combination of the definite-time OC functions (50P and 50G) and the inverse-time OC functions (51P and 51G) in the same OCR to get the adaptable and scalable DN protection system. Full article

(This article belongs to the Special Issue Electric Power Applications)

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17 pages, 3229 KiB

Open AccessArticle

Evaluation of the Simultaneous Operation of the Mechanisms for Cross-Border Interchange and Activation of the Regulating Reserves

by Marcel Topler and Boštjan Polajžer

Appl. Sci. 2021, 11(17), 8188; https://doi.org/10.3390/app11178188 - 3 Sep 2021

Cited by 1 | Viewed by 1498

Abstract

This article examines the mechanisms for cross-border interchange of the regulating reserves (RRs), i.e., the imbalance-netting process (INP) and the cross-border activation of the RRs (CBRR). Both mechanisms are an additional service of frequency restoration reserves in the power system and connect different [...] Read more.

This article examines the mechanisms for cross-border interchange of the regulating reserves (RRs), i.e., the imbalance-netting process (INP) and the cross-border activation of the RRs (CBRR). Both mechanisms are an additional service of frequency restoration reserves in the power system and connect different control areas (CAs) via virtual tie-lines to release RRs and reduce balancing energy. The primary objective of the INP is to net the demand for RRs between the cooperating CAs with different signs of interchange power variation. In contrast, the primary objective of the CBRR is to activate the RRs in the cooperating CAs with matching signs of interchange power variation. In this way, the ancillary services market and the European balancing system should be improved. However, both the INP and CBRR include a frequency term and thus impact the frequency response of the cooperating CAs. Therefore, the impact of the simultaneous operation of the INP and CBRR on the load-frequency control (LFC) and performance is comprehensively evaluated with dynamic simulations of a three-CA testing system, which no previous studies investigated before. In addition, a function for correction power adjustment is proposed to prevent the undesirable simultaneous activation of the INP and CBRR. In this way, area control error (ACE) and scheduled control power are decreased since undesired correction is prevented. The dynamic simulations confirmed that the simultaneous operation of the INP and CBRR reduced the balancing energy and decreased the unintended exchange of energy. Consequently, the LFC and performance were improved in this way. However, the impact of the INP and CBRR on the frequency quality has no unambiguous conclusions. Full article

(This article belongs to the Special Issue Electric Power Applications)

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14 pages, 2017 KiB

Open AccessArticle

A Fault Analysis Method Based on Association Rule Mining for Distribution Terminal Unit

by Xuecen Zhang, Yi Tang, Qiang Liu, Guofeng Liu, Xin Ning and Jiankun Chen

Appl. Sci. 2021, 11(11), 5221; https://doi.org/10.3390/app11115221 - 4 Jun 2021

Cited by 13 | Viewed by 2321

Abstract

With the development of distribution networks, large amounts of distribution terminal units (DTU) are gradually integrated into the power system. However, limited numbers of maintenance engineers can hardly cope with the pressure brought about by the substantial increase of DTU devices. As DTU [...] Read more.

With the development of distribution networks, large amounts of distribution terminal units (DTU) are gradually integrated into the power system. However, limited numbers of maintenance engineers can hardly cope with the pressure brought about by the substantial increase of DTU devices. As DTU fault would pose a threat to the stable and safe operation of power systems; thus, it is rather significant to reduce the fault incidence of DTU devices and improve the efficiency of fault elimination. In this paper, a DTU fault analysis method using an association rule mining algorithm was proposed. Key factors of DTU fault were analyzed at first. Then, the main concept of the Eclat algorithm was illustrated, and its performance was compared with FP-growth and Apriori algorithms using DTU fault databases of different sizes. Afterwards, a DTU fault analysis method based on the Eclat algorithm was proposed. The practicality of this method was proven by experiment using a realistic DTU fault database. Finally, the application of this method was presented to demonstrate its effectiveness. Full article

(This article belongs to the Special Issue Electric Power Applications)

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20 pages, 7733 KiB

Open AccessArticle

Improved PR Control Strategy for an LCL Three-Phase Grid-Connected Inverter Based on Active Damping

by Yahui Li, Jing Zhang, Zhenghang Hao and Peng Tian

Appl. Sci. 2021, 11(7), 3170; https://doi.org/10.3390/app11073170 - 2 Apr 2021

Cited by 10 | Viewed by 3199

Abstract

Aiming at the problem of power coupling and complicated decoupling in the d-q coordinate system of a three-phase grid-connected inverter, a current closed-loop control strategy based on an improved QPIR (quasi-proportional integral resonant) controller in the α-β two-phase static [...] Read more.

Aiming at the problem of power coupling and complicated decoupling in the d-q coordinate system of a three-phase grid-connected inverter, a current closed-loop control strategy based on an improved QPIR (quasi-proportional integral resonant) controller in the α-β two-phase static coordinate system is proposed. Firstly, the mathematical model of an LCL three-phase grid-connected inverter is established, and its instantaneous power calculation equation is deduced. Secondly, the frequency method is applied to compare and analyze the proportional resonant, quasi-proportional resonant, and improved current controller, and the appropriate improved controller parameters are obtained according to the traditional proportional integral controller parameter design method and the weight coefficient. Finally, the improved controller is compared with the traditional controller in the simulation model of the LCL three-phase grid-connected inverter based on active damping. The results show that the proposed improved current control strategy has good dynamic response characteristics, can realize the non-static error control of grid-connected current, and realizes the decoupling control of active power and reactive power when the load jumps. At the same time, the results also prove the superiority of the proposed control strategy and verify its effectiveness. Full article

(This article belongs to the Special Issue Electric Power Applications)

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Review

Jump to: Research

21 pages, 3219 KiB

Open AccessReview

Energy Harvesting Methods for Transmission Lines: A Comprehensive Review

by Jordi-Roger Riba, Manuel Moreno-Eguilaz and Santiago Bogarra

Appl. Sci. 2022, 12(21), 10699; https://doi.org/10.3390/app122110699 - 22 Oct 2022

Cited by 18 | Viewed by 7188

Abstract

Humanity faces important challenges concerning the optimal use, security, and availability of energy systems, particularly electrical power systems and transmission lines. In this context, data-driven predictive maintenance plans make it possible to increase the safety, stability, reliability, and availability of electrical power systems. [...] Read more.

Humanity faces important challenges concerning the optimal use, security, and availability of energy systems, particularly electrical power systems and transmission lines. In this context, data-driven predictive maintenance plans make it possible to increase the safety, stability, reliability, and availability of electrical power systems. In contrast, strategies such as dynamic line rating (DLR) make it possible to optimize the use of power lines. However, these approaches require developing monitoring plans based on acquiring electrical data in real-time using different types of wireless sensors placed in strategic locations. Due to the specific conditions of the transmission lines, e.g., high electric and magnetic fields, this a challenging problem, aggravated by the harsh outdoor environments where power lines are built. Such sensors must also incorporate an energy harvesting (EH) unit that supplies the necessary electronics. Therefore, the EH unit plays a key role, so when designing such electronic systems, care must be taken to select the most suitable EH technology, which is currently evolving rapidly. This work reviews and analyzes the state-of-the-art technology for EH focused on transmission lines, as it is an area with enormous potential for expansion. In addition to recent advances, it also discusses the research needs and challenges that need to be addressed. Despite the importance of this topic, there is still much to investigate, as this area is still in its infancy. Although EH systems for transmission lines are reviewed, many other applications could potentially benefit from introducing wireless sensors with EH capabilities, such as power transformers, distribution switches, or low- and medium-voltage power lines, among others. Full article

(This article belongs to the Special Issue Electric Power Applications)

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