scholarly journals Development of New Protection Scheme in DC Microgrid Using Wavelet Transform

Energies ◽  
2022 ◽  
Vol 15 (1) ◽  
pp. 283
Author(s):  
Hun-Chul Seo
Keyword(s):  
Wavelet Transform ◽  
Low Voltage ◽  
Rapid Development ◽  
Circuit Breaker ◽  
Stable Operation ◽  
Fault Current ◽  
Pv System ◽  
Dc Microgrid ◽  
Protection Scheme ◽  
Protection Method

The demand for a low voltage direct current (LVDC) microgrid is increasing by the increase of DC-based digital loads and renewable resources and the rapid development of power electronics technology. For the stable operation of an LVDC microgrid, it is necessary to develop a protection method. In this paper, the new protection scheme considering the fault section is proposed using wavelet transform (WT) in an LVDC microgrid. The fault sections are classified into DC side of the alternating current (AC)/DC converter, DC/DC converter connected to photovoltaic (PV) system, DC line, and DC bus. The characteristics of fault current at each fault section are analyzed. Based on these analyses, the new protection scheme including the fault section estimation is proposed using WT. The proposed scheme estimates the fault section using the detail component after performing WT and sends the trip signal to each circuit breaker according to the fault section. The proposed protection scheme is verified through various simulations according to the fault region and fault current using electromagnetic transient program (EMTP)/ATPDraw and MATLAB. The simulation results show that the fault section is accurately determined, and the corresponding circuit breaker (CB) operations are performed.

scholarly journals Fault Section Estimation in Radial LVDC Distribution System Using Wavelet Transform

Energies ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 8486
Author(s):  
Hun-Chul Seo ◽  
Gi-Hyeon Gwon ◽  
Keon-Woo Park
Keyword(s):  
Wavelet Transform ◽  
Distributed Generation ◽  
Distribution System ◽  
Distribution Systems ◽  
Low Voltage ◽  
Rapid Development ◽  
Power Conversion ◽  
Stable Operation ◽  
Protection Method ◽  
Dc Line

The demand for low voltage DC (LVDC) distribution systems is increasing due to the rapid development of power conversion technology, the increase of DC-based digital loads, and the expansion of DC-based distributed generation (DG). For the stable operation of the LVDC distribution system, it is necessary to develop a protection method. In this paper, the fault section is estimated using wavelet transform (WT) in LVDC distribution system. The fault section is classified into a DC line and a DC bus. The characteristics of fault current at each fault section part are analyzed in simple and actual LVDC system. Based on this analysis, the algorithm for fault section estimation is proposed using the detail component after performing WT. The results of fault section estimations are verified through various simulations using EMTP and MATLAB. The fault section estimation can be utilized in the development of protection schemes in LVDC distribution system.

Protection Scheme for DC Microgrid Distribution System

2012 ◽  
Vol 614-615 ◽  
pp. 1661-1665
Author(s):  
Ling Hui Deng ◽  
Zhi Xin Wang ◽  
Jian Min Duan
Keyword(s):  
Distribution System ◽  
Cost Efficiency ◽  
Power Flow ◽  
Low Voltage ◽  
Dc Microgrid ◽  
Protection Scheme ◽  
High Level ◽  
Bidirectional Power Flow ◽  
Efficiency And Reliability ◽  
Laboratory Prototype

The low voltage DC (LVDC) distribution system is a new concept and a promising technology to be used in the future smart distribution system having high level cost-efficiency and reliability. In this paper, a low-voltage (LV) DC microgrid protection system design is proposed. Usually, an LVDC microgrid must be connected to an ac grid through converters with bidirectional power flow and, therefore, a different protection scheme is needed. This paper describes practical protection solutions for the LVDC network and an LVDC system laboratory prototype is being experimentally tested by MATLAB/SIMULINK. The results show that it is possible to use available devices to protect such a system. But other problems may arise which needs further study.

scholarly journals Development of a Voltage Compensation Type Active SFCL and Its Application for Transient Performance Enhancement of a PMSG-Based Wind Turbine System

2017 ◽  
Vol 2017 ◽  
pp. 1-12
Author(s):  
Lei Chen ◽  
Hongkun Chen ◽  
Jun Yang ◽  
Huiwen He
Keyword(s):  
Wind Turbine ◽  
Performance Enhancement ◽  
Low Voltage ◽  
Rapid Development ◽  
Test System ◽  
Voltage Source ◽  
Voltage Source Converter ◽  
Fault Current ◽  
Wind Turbine System ◽  
Voltage Compensation

Considering the rapid development of high temperature superconducting (HTS) materials, superconducting power applications have attracted more and more attention in the power industry, particularly for electrical systems including renewable energy. This paper conducts experimental tests on a voltage compensation type active superconducting fault current limiter (SFCL) prototype and explores the SFCL’s application in a permanent-magnet synchronous generator- (PMSG-) based wind turbine system. The SFCL prototype is composed of a three-phase air-core superconducting transformer and a voltage source converter (VSC) integrated with supercapacitor energy storage. According to the commissioning test and the current-limiting test, the SFCL prototype can automatically suppress the fault current and offer a highly controlled compensation voltage in series with the 132 V electrical test system. To expand the application of the active SFCL in a 10 kW class PMSG-based wind turbine system, digital simulations under different fault cases are performed in MATLAB/Simulink. From the demonstrated simulation results, using the active SFCL can help to maintain the power balance, mitigate the voltage-current fluctuation, and improve the wind energy efficiency. The active SFCL can be regarded as a feasible solution to assist the PMSG-based wind turbine system to achieve low-voltage ride-through (LVRT) operation.

scholarly journals Bidirectional Short-Circuit Current Blocker for DC Microgrid Based on Solid-State Circuit Breaker

Electronics ◽  
2020 ◽  
Vol 9 (2) ◽  
pp. 306 ◽  
Author(s):  
Lujun Wang ◽  
Boyu Feng ◽  
Yu Wang ◽  
Tiezhou Wu ◽  
Huipin Lin
Keyword(s):  
Solid State ◽  
Low Voltage ◽  
Short Circuit ◽  
Circuit Breaker ◽  
Short Circuit Current ◽  
Rotational Inertia ◽  
Dc Microgrid ◽  
Protection Strategy ◽  
Solid State Circuit ◽  
Solid State Circuit Breaker

In order to solve the imminent problem in that the traditional protection strategy cannot meet time requirements, together with the fact that the rotational inertia of a DC microgrid is small and short-circuit fault develops rapidly, a bidirectional short-circuit current blocker (BSCCB) based on solid-state circuit breaker for a DC microgrid is proposed. Firstly, the bidirectional current blocking circuit structure is proposed based on the analysis of key components. Then, a top-level differential protection strategy is developed based on the aforementioned proposal. Finally, the performance of the blocking circuit is simulated and verified by experiments. The results show that the proposed method can block short-circuit current within 4 ms, and the response speed of the protection strategy is very fast compared with previous approaches. BSCCB also has reclosing, bidirectional blocking and energy releasing functions. The current blocker proposed in this paper can be reused multiple times and has a promising future in low-voltage DC microgrid application.

scholarly journals Differential Protection of Power Transformer using Wavelet Transform

2019 ◽  
Vol 8 (3) ◽  
pp. 7627-7630
Keyword(s):  
Wavelet Transform ◽  
Power Transformer ◽  
Circuit Breaker ◽  
Inrush Current ◽  
Differential Protection ◽  
Time Duration ◽  
Transform Method ◽  
Protection Scheme ◽  
Magnetizing Inrush Current ◽  
Clearing Time

This paper presents wavelet transform method for the analysis of differential currents of power transformer which can act as an accurate classifier between magnetizing inrush current and internal faults to avoid the needless tripping of circuit breaker. The differential protection scheme occasionally mal – operate whenever magnetizing inrush occurs in power transformer. The aim is to reduce the rate and time duration of undesired outages of power transformer. This includes the necessities of reliability with zero mal – operation of differential relay. The result shows higher operating speed with less fault clearing time. Wavelet Transform is employed for the analysis of transient signals under various conditions, which extracts data from signals in time and frequency domain simultaneously. The simulation is done in MATLAB environment.

An Improved Method of Solid State Circuit Breaker in Low Voltage DC Microgrid

2021 ◽  
Author(s):  
Lingyu Sun ◽  
Song Tang ◽  
Pengcheng Wang ◽  
Junfei Han ◽  
Yuqiang Wang ◽  
...  
Keyword(s):  
Solid State ◽  
Low Voltage ◽  
Circuit Breaker ◽  
Improved Method ◽  
Dc Microgrid ◽  
Solid State Circuit ◽  
Solid State Circuit Breaker

scholarly journals Decentralized Plug-and-Play Protection Scheme for Low Voltage DC Grids

Energies ◽  
2020 ◽  
Vol 13 (12) ◽  
pp. 3167
Author(s):  
Nils H. van der Blij ◽  
Pavel Purgat ◽  
Thiago B. Soeiro ◽  
Laura M. Ramirez-Elizondo ◽  
Matthijs T. J. Spaan ◽  
...  
Keyword(s):  
Solid State ◽  
Fault Detection ◽  
Low Voltage ◽  
Circuit Breaker ◽  
Circuit Breakers ◽  
Plug And Play ◽  
Zero Crossing ◽  
Protection Scheme ◽  
Selective Protection ◽  
Solid State Circuit Breaker

Since the voltages and currents in dc grids do not have a natural zero-crossing, the protection of these grids is more challenging than the protection of conventional ac grids. Literature presents several unit and non-unit protection schemes that rely on communication, or knowledge about the system’s topology and parameters in order to achieve selective protection in these grids. However, communication complicates fast fault detection and interruption, and a system’s parameters are subject to uncertainty and change. This paper demonstrates that, in low voltage dc grids, faults propagate fast through the grid and interrupted inductive currents commutate to non-faulted sections of the grid, which both can cause circuit breakers in non-faulted sections to trip. A decentralized plug-and-play protection scheme is proposed that ensures selectivity via an augmented solid-state circuit breaker topology and by utilizing the proposed time-current characteristic. It is experimentally shown that the proposed scheme provides secure and selective fault interruption for radial and meshed low voltage dc grids under various conditions.

A fault detection technique based on line parameters in ring-configured DC microgrid

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Satyavarta Kumar Prince ◽  
Shaik Affijulla ◽  
Gayadhar Panda
Keyword(s):  
Fault Detection ◽  
Sudden Change ◽  
Least Square ◽  
Detection Technique ◽  
Fault Estimation ◽  
Fault Current ◽  
Dc Microgrid ◽  
Zero Crossing ◽  
Protection Scheme ◽  
Dc Fault

Abstract The integration of distributed generation (DG) units into a DC microgrid presents a research challenge in terms of a proper protection scheme. The network must be protected due to the sudden change in the amplitude and direction of the fault current. In addition, due to the absence of zero-crossing of the DC fault current, protecting the network from these potential faults is a challenging task. The DC fault can be diagnosed using an appropriate detection technique after monitoring the movement of current. In this paper, a least-square estimation (LSE) technique has been adopted, which has been proven to be able to detect the faulty line strongly, so that the fault is detected by estimated parameters. This fault detection technique has been evaluated on six-lines, with faults analyzed on each line. The six-bus DC microgrid is designed in PSS®SINCAL, and the proposed method is simulated in MATLAB. Two sets of simulations are designed to validate the reliability of the proposed method: (1) pole–ground (P–G) and (2) pole–pole (P–P) fault estimation of inductance and capacitance (C) in a separate line. Simulation results show that the proposed methodology can able to accurately detect (i.e., 95% accuracy) the faulty line in the DC microgrid with respect to designated ‘trip’ value. Thus, the proposed fault detection methodology can be utilized for protection of modern DC microgrids. An experimental PV-battery-load-based fault detection technique has been developed in the laboratory and tested under P–P fault conditions in order to validate the effectiveness of the proposed scheme.

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