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.

scholarly journals Fault Detection in DC Microgrids Using Short-Time Fourier Transform

Energies ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 277
Author(s):  
Ivan Grcić ◽  
Hrvoje Pandžić ◽  
Damir Novosel
Keyword(s):  
Fourier Transform ◽  
Fault Detection ◽  
Operating Conditions ◽  
Time Signal ◽  
Short Time Fourier Transform ◽  
Dc Microgrid ◽  
Protection Scheme ◽  
Simulink Model ◽  
Battery Energy ◽  
Short Time

Fault detection in microgrids presents a strong technical challenge due to the dynamic operating conditions. Changing the power generation and load impacts the current magnitude and direction, which has an adverse effect on the microgrid protection scheme. To address this problem, this paper addresses a field-transform-based fault detection method immune to the microgrid conditions. The faults are simulated via a Matlab/Simulink model of the grid-connected photovoltaics-based DC microgrid with battery energy storage. Short-time Fourier transform is applied to the fault time signal to obtain a frequency spectrum. Selected spectrum features are then provided to a number of intelligent classifiers. The classifiers’ scores were evaluated using the F1-score metric. Most classifiers proved to be reliable as their performance score was above 90%.

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.

scholarly journals Appropriate Protection Scheme for DC Grid Based on the Half Bridge Modular Multilevel Converter System

Energies ◽  
2019 ◽  
Vol 12 (10) ◽  
pp. 1837 ◽  
Author(s):  
Ho-Yun Lee ◽  
Mansoor Asif ◽  
Kyu-Hoon Park ◽  
Hyun-Min Mun ◽  
Bang-Wook Lee
Keyword(s):  
Energy Dissipation ◽  
Circuit Breaker ◽  
Fault Current ◽  
Modular Multilevel Converter ◽  
Fault Current Limiter ◽  
Operating Characteristics ◽  
Multilevel Converter ◽  
Protection Scheme ◽  
Dc Fault ◽  
Current Limiter

The half bridge (HB) modular multilevel converter (MMC) technology is considered a breakthrough to mitigate the shortcomings of the conventional voltage source converter (VSC) in high-voltage direct-current (HVDC) grid application. However, interruption of the DC fault is still a challenge due to fast di/dt and extremely high levels of DC fault current. The fault interruption using a DC circuit breaker (DCCB) causes enormous energy dissipation and voltage stress across the DCCB. Therefore, the use of a fault current limiter is essential, and the superconducting fault current limiter (SFCL) is the most promising choice. Past literature has focused on the operating characteristics of DCCB or limiting characteristics of the SFCL. However, there is little understanding about the fault interruption and system recovery characteristics considering both DCCB and SFCL. In this paper, we have presented a comparative study on fault interruption and system recovery characteristics considering three types of fault limiting devices in combination with circuit breaker. The transient analyses of AC and DC system have been performed, to suggest the most preferable protection scheme. It has been concluded that, amongst the three fault limiting devices, the Hybrid SFCL in combination with circuit breaker, delivers the most desirable performance in terms of interruption time, recovery time, energy dissipation and voltage transients.

scholarly journals Model-Based Fault Detection of Inverter-Based Microgrids and a Mathematical Framework to Analyze and Avoid Nuisance Tripping and Blinding Scenarios

Energies ◽  
2018 ◽  
Vol 11 (8) ◽  
pp. 2152 ◽  
Author(s):  
Hashim Al Hassan ◽  
Andrew Reiman ◽  
Gregory Reed ◽  
Zhi-Hong Mao ◽  
Brandon Grainger
Keyword(s):  
Fault Detection ◽  
Low Voltage ◽  
Detection Technique ◽  
Mathematical Framework ◽  
Fault Current ◽  
Low Voltage Ride Through ◽  
Model Based ◽  
Wide Range ◽  
Nuisance Tripping ◽  
Dynamic Relationships

Traditional protection methods such as over-current or under-voltage methods are unreliable in inverter-based microgrid applications. This is primarily due to low fault current levels because of power electronic interfaces to the distributed energy resources (DER), and IEEE1547 low-voltage-ride-through (LVRT) requirements for renewables in microgrids. However, when faults occur in a microgrid feeder, system changes occur which manipulate the internal circuit structure altering the system dynamic relationships. This observation establishes the basis for a proposed, novel, model-based, communication-free fault detection technique for inverter-based microgrids. The method can detect faults regardless of the fault current level and the microgrid mode of operation. The approach utilizes fewer measurements to avoid the use of a communication system. Protecting the microgrid without communication channels could lead to blinding (circuit breakers not tripping for faults) or nuisance tripping (tripping incorrectly). However, these events can be avoided with proper system design, specifically with appropriately sized system impedance. Thus, a major contribution of this article is the development of a mathematical framework to analyze and avoid blinding and nuisance tripping scenarios by quantifying the bounds of the proposed fault detection technique. As part of this analysis, the impedance based constraints for microgrid system feeders are included. The performance of the proposed technique is demonstrated in the MATLAB/SIMULINK (MathWorks, Natick, MA, USA) simulation environment on a representative microgrid architecture showing that the proposed technique can detect faults for a wide range of load impedances and fault impedances.

scholarly journals Simulation Test of a DC Fault Current Limiter for Fault Ride-Through Problem of Low-Voltage DC Distribution

Energies ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1753 ◽  
Author(s):  
Bing Han ◽  
Yonggang Li
Keyword(s):  
Fault Detection ◽  
Low Voltage ◽  
Short Circuit ◽  
Distribution Network ◽  
Fault Current ◽  
Fault Current Limiter ◽  
Dc Fault ◽  
Fault Ride Through ◽  
Current Limiter ◽  
Short Circuit Fault

The low voltage direct current (LVDC) distribution networks are connected with too many kinds of loads and sources, which makes them prone to failure. Due to the small damping value in the DC lines, the fault signal propagates so fast that the impact current with the wave front of millisecond and the transient voltage pose great challenges for fault detection. Even worse, some faults with small currents are difficult to detect and the communication is out of sync, resulting in protection misoperation. These problems have severely affected the new energy utilization. In view of this, a DC fault current limiter (FCL) composed of inductance, resistance, and power electronic switch was designed in this paper. The rising speed of fault current can be decreased by the series inductance and the peak value of the fault current can be limited by series impedance, thus in this way the running time can be gained for fault detection and protection. For distributed energy access, by deducing the short circuit fault characteristic expression of LVDC distribution network, the feasibility of FCL was verified. Based on the structure of the bridge-type alternating current (AC) current limiter, the structure and parameters of the DC FCL were determined according to the fault ride-through target. Then, a low voltage ride-through strategy based on DC FCL was proposed for the bipolar short-circuit fault of LVDC distribution network. Finally, MATLAB/Simulink simulation was used to verify the rationality of the proposed FCL and its ride-through strategy.

scholarly journals A di/dt Detection Circuit for DC Unidirectional Breaker Based on Inductor Transient Behaviour

2021 ◽  
Vol 13 (16) ◽  
pp. 9466
Author(s):  
Jeziel Vázquez ◽  
Elias J. J. Rodriguez ◽  
Jaime Arau ◽  
Nimrod Vázquez
Keyword(s):  
Steady State ◽  
Fault Detection ◽  
Short Circuit ◽  
Fault Current ◽  
Dc Microgrid ◽  
Transient Behaviour ◽  
Detection Circuit ◽  
Circuit Structure ◽  
Dc Breaker ◽  
Proper Operation

In this paper, a di/dt detection circuit for DC breaker applications is proposed to provide faster short-circuit and overcurrent fault detection, where DC breakers are required to be designed for unidirectional fault current conditions, which is a challenge regarding DC microgrid applications due to some associated problems such as long periods of fault interruption, complex circuit structure, and low reliability. The proposal, which is based on measurement of di/dt, can detect fault current conditions for different distances from the point of failure, and is suitable to operation in both islanding and grid-connected conditions. The proposed circuit was studied theoretically and experimentally in steady state, as well as under load changes and short circuit conditions to ensure proper operation, making this solution a fast current fault detection solution, which is a significant advantage and requirement in DC microgrid applications.

scholarly journals Integrated Control and Protection Architecture for Islanded PV-Battery DC Microgrids: Design, Analysis and Experimental Verification

2020 ◽  
Vol 10 (24) ◽  
pp. 8847
Author(s):  
Ali Abdali ◽  
Kazem Mazlumi ◽  
Josep M. Guerrero
Keyword(s):  
Fault Detection ◽  
Integrated Control ◽  
Storage System ◽  
Energy Storage System ◽  
Detection Algorithm ◽  
Dc Microgrid ◽  
Dc Microgrids ◽  
Protection Scheme ◽  
Bus Voltage ◽  
Battery Energy

Direct current (dc) microgrids have gained significant interest in research due to dc generation/storage technologies—such as photovoltaics (PV) and batteries—increasing performance and reducing in cost. However, proper protection and control systems are critical in order to make dc microgrids feasible. This paper aims to propose a novel integrated control and protection scheme by using the state-dependent Riccati equation (SDRE) method for PV-battery based islanded dc microgrids. The dc microgrid under study consists of photovoltaic (PV) generation, a battery energy storage system (BESS), a capacitor bank and a dc load. The aims of this study are fast fault detection and voltage control of the dc load bus. To do so, the SDRE observer-controller—a nonlinear mathematical model—is employed to model the operation of the dc microgrid. Simulation results show that the proposed SDRE method is effective for fault detection and robust against external disturbances, resulting in it being capable of controlling the dc load bus voltage during disturbances. Finally, the dc microgrid and its proposed protection scheme are implemented in an experimental testbed prototype to verify the fault detection algorithm feasibility. The experimental results indicate that the SDRE scheme can effectively detect faults in a few milliseconds.

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