scholarly journals Assessment of MOV Deterioration under Energized Conditions

Energies ◽  
2020 ◽  
Vol 13 (15) ◽  
pp. 4018
Author(s):  
Sung-Wook Kim ◽  
Nam-Hoon Kim ◽  
Gyung-suk Kil
Keyword(s):  
Short Circuit ◽  
Electronic Devices ◽  
Leakage Currents ◽  
Manufacturing Defects ◽  
Accelerated Degradation ◽  
Ground Fault ◽  
Voltage Variation ◽  
Reliable Assessment ◽  
Different Types ◽  
Surge Current

Metal oxide varistors (MOVs) are widely used to protect electrical and electronic devices that are very vulnerable to surges due to the low insulation level of the equipment. MOVs deteriorate gradually due to manufacturing defects, mechanical and thermal stress, or repeated protective operations against surges. These defects result in the thermal runaway of MOV and finally lead to the explosion and electric fire of electrical and electronic devices due to a short circuit and a line-to-ground fault. Therefore, the reliable assessment of the condition of MOV deterioration is required for electrical and electronic equipment. However, when most accelerated degradation tests for the MOV have been performed to date, an 8/20 μs standard surge current is applied under de-energized conditions, which is unlike the actual operating environment. In this study, a surge generator was designed to apply a surge current to MOVs to monitor their deterioration. Three different types of leakage currents were measured to analyze the change rates of their electrical characteristics of MOVs by comparing them with the reference voltage variation. Furthermore, the condition assessment of MOV deterioration under energized and de-energized conditions was investigated.

scholarly journals Detecting the single line to ground short circuit fault in the submarine’s power system using the artificial neural network

2013 ◽  
Vol 10 (3) ◽  
pp. 445-457
Author(s):  
Ali Behniafar ◽  
Ahmad Darabi ◽  
Mahdi Banejad ◽  
Mohammadreza Baghayipour
Keyword(s):  
Neural Network ◽  
Power Systems ◽  
Power System ◽  
Short Circuit ◽  
Single Line ◽  
Special Importance ◽  
Double Line ◽  
Ground Fault ◽  
Different Types ◽  
Short Circuit Fault

The electric marine instruments are newly inserted in the trade and industry, for which the existence of an equipped and reliable power system is necessitated. One of the features of such a power system is that it cannot have an earth system causing the protection relays not to be able to detect the single line to ground short circuit fault. While on the other hand, the occurrence of another similar fault at the same time can lead to the double line fault and thereby the tripping of relays and shortening of vital loads. This in turn endangers the personals' security and causes the loss of military plans. From the above considerations, it is inferred that detecting the single line to ground fault in the marine instruments is of a special importance. In this way, this paper intends to detect the single line to ground fault in the power systems of the marine instruments using the wavelet transform and Multi-Layer Perceptron (MLP) neural network. In the numerical analysis, several different types of short circuit faults are simulated on several marine power systems and the proposed approach is applied to detect the single line to ground fault. The results are of a high quality and preciseness and perfectly demonstrate the effectiveness of the proposed approach.

scholarly journals Comparison of Thermal Stress during Short-Circuit in Different Types of 1.2 kV SiC Transistors Based on Experiments and Simulations

2017 ◽  
Vol 897 ◽  
pp. 595-598
Author(s):  
Diane Perle Sadik ◽  
Jang Kwon Lim ◽  
Juan Colmenares ◽  
Mietek Bakowski ◽  
Hans Peter Nee
Keyword(s):  
Thermal Stress ◽  
Short Circuit ◽  
Thermal Simulation ◽  
Temperature Evolution ◽  
Power Devices ◽  
Different Types ◽  
Transient Thermal

The temperature evolution during a short-circuit in the die of three different Silicon Carbide1200-V power devices is presented. A transient thermal simulation was performed based on the reconstructedstructure of commercially available devices. The location of the hottest point in the device iscompared. Finally, the analysis supports the necessity to turn off short-circuit events rapidly in orderto protect the device after a fault.

scholarly journals Complex Electronic Protection for Low-voltage Three-phase Induction Motors

2020 ◽  
Vol 11 ◽  
pp. 11-17
Author(s):  
Gabriel Nicolae Popa ◽  
Corina Maria Diniș
Keyword(s):  
Induction Motors ◽  
Low Voltage ◽  
Short Circuit ◽  
Electronic Devices ◽  
General Purpose ◽  
Two Phase ◽  
Dc Voltage ◽  
Electric Drives ◽  
Normal Limits ◽  
Three Phase

Low-voltage three-phase induction motors are most often used in industrial electric drives. Electric motors must be protected by electric and/or electronic devices against: short-circuit, overloads, asymmetrical currents, two-phase voltage operation, under-voltage, and over-temperature. To design the electronic protection currents, voltages and temperature must be measured to determine whether they fall within normal limits. The electronic protection was design into low capacity PLC. The paper presents the designs and analysis of complex electronic protection for general purpose low-voltage three-phase induction motors. The electronic protection has Hall transducers and conversion electronic devices for AC currents to DC voltages, AC voltages to DC voltage, temperature to DC voltage, a low capacity PLC, switches, motor’s power contactors, and signalling lamps has been developed. Experiments with complex electronic protection, for different faults are presented. The proposed protection has the advantages of incorporating all usual protections future for the low-voltage three-phase induction motors.

Design of Accelerated Degradation Test Method and Failure Analysis of Flexible Hybrid Electronic Devices

2020 ◽  
Author(s):  
Alex Davila-Frias ◽  
Val Marinov ◽  
Om Prakash Yadav ◽  
Yuriy Atanasov
Keyword(s):  
Failure Analysis ◽  
Failure Process ◽  
Electronic Devices ◽  
Test Method ◽  
Stress Factors ◽  
Accelerated Degradation ◽  
Failure Data ◽  
Degradation Data ◽  
Accelerated Life ◽  
Temperature And Humidity

Abstract Accelerated life testing (ALT) has been a common choice to study the effects of environmental stresses on flexible hybrid electronics (FHE), a promising technology to produce flexible electronic devices. Nevertheless, accelerated degradation testing (ADT) has proven to be a more effective approach, which does not require failure occurrences, allowing shorter testing times. Since FHE devices are expected to be highly reliable, ADT provides useful information in the form of degradation data for further analysis without actual failure data. In this paper, we present the design and experimental setup of ADT for FHE considering two stress factors simultaneously. We use daisy-chain resistance as a measurable degradation characteristic to periodically monitor the degradation of FHE products under accelerated stress conditions. Two stress factors, temperature and humidity, are considered and ADT was carried out considering four combinations of temperature and humidity simultaneously. Failure analysis was performed on failed units to investigate the failure process and location of the failure. The ADT data was used to fit in the appropriate mathematical degradation model representing the failure process. The data analysis showed faster degradation paths for higher stress combinations. Finally, we present insights and further research opportunities to expand the work.

scholarly journals Behavior of an Inductive Loop Sensor in the Measurement of Partial Discharge Pulses with Variations in Its Separation from the Primary Conductor

Sensors ◽  
2018 ◽  
Vol 18 (7) ◽  
pp. 2324 ◽  
Author(s):  
Jorge Ardila-Rey ◽  
Aldo Barrueto ◽  
Alvaro Zerene ◽  
Bruno Castro ◽  
José Ulson ◽  
...  
Keyword(s):  
Short Circuit ◽  
Partial Discharges ◽  
Active Components ◽  
Insulation System ◽  
Small Current ◽  
Inductive Loop ◽  
Fixed Distance ◽  
Different Types ◽  
Current Design ◽  
Insulating Properties

Ideally, an insulation system must be capable of electrically insulating the active components of a machine or device subjected to high voltages. However, due to the presence of polluting agents or imperfections inside or on the surface of the insulation, small current pulses called partial discharges (PDs) are common, which partially short-circuit the insulation and cause it to lose its insulating properties, and thus its insulation capacity, over time. In some cases, measurements of this phenomenon are limited by the type of sensor used; if it is not adequate, it can distort the obtained results, which can lead to a misdiagnosis of the state of the device. The inductive loop sensor has experimentally been demonstrated to be capable of properly measuring different types of PDs. However, because of its current design, there are several practical limitations on its use in real devices or environments. An example is the presence of a primary conductor located at a fixed distance from the sensor, through which PD pulses must flow for the sensor to capture them. In this article, the sensor’s behavior is studied at different separation distances from the line through which the PD pulses flow. In addition, the measuring capacity of the sensor is tested by removing the presence of the primary conductor and placing the sensor directly over the line through which the PD pulses of a real device flow.

Experimental Study of Electric Bicycle Charging Fault Simulation

2014 ◽  
Vol 575 ◽  
pp. 837-840
Author(s):  
Ying Wu
Keyword(s):  
Experimental Study ◽  
Temperature Rise ◽  
Short Circuit ◽  
Fault Simulation ◽  
Electronic Devices ◽  
Protective Device ◽  
Lead Acid Battery ◽  
Limited Temperature ◽  
Electric Bicycle ◽  
Electric Bicycles

This article selects an intelligent pulse three-stage charger commonly used in electric bicycles and conducts fault simulation tests of the charger under different environmental conditions based on analysis of the charging characteristics of a lead-acid battery. The test proves that the fault of the charger may lead to breakdown or explosion of the electronic devices of the charger; however, the possibility of a fire inside the charger is very small because of limited temperature rise of heating components in the charger, a small amount of combustible materials in the components, flame retardant plastics-made charger housing, etc. A fire inside the charger easily results in short circuit of connecting lines. If there is no a protective device, the electric bicycle easily catches fire.

Studying Pressure Induced Whiskers Formation from Sn-Rich Surfaces

2014 ◽  
Vol 790-791 ◽  
pp. 271-276 ◽  
Author(s):  
Anna Sycheva ◽  
Adam Radanyi ◽  
Zoltán Gácsi
Keyword(s):  
Heat Treatment ◽  
Mechanical Load ◽  
Short Circuit ◽  
Electronic Devices ◽  
Control Unit ◽  
Tin Whiskers ◽  
Tin Whisker ◽  
Electron Microscopic ◽  
Scanning Electron Microscopic ◽  
Sem Imaging

Whiskers formed on the lead-free tin surfaces pose a serious risk to small electronic devices causing a short circuit and leading to the component/device failure. The present research was focused on the investigation of tin whisker formation on a motor control unit sockets made of tin coated copper, applying to the specimen mechanical load alone or together with heat treatment/electric current. Scanning Electron Microscopic (SEM) imaging was applied in order to study the microstructure of tin whiskers obtained, their length and number at the boundary of each imprint. If the mechanical stress increases from 1000 to 5000 MPa, the average number of whiskers and possible formation spots also increase from 570 to 1300. The length of whiskers varied from 3 μm after 0.5 h to 5.5 μm after 3 hours of exposition. It has been found that heat treatment at 150°C for 1 hour significantly reduces the number of whiskers (on average 6 times as few) formed. Therefore, the threat of failure of the electronic equipment is reduced.

Calculation and Analysis of Three-Phase Transformer Short-Circuit Current

2014 ◽  
Vol 986-987 ◽  
pp. 1914-1917
Author(s):  
Pei Ming Pan ◽  
Huan Lian ◽  
Fei Xiang Hui ◽  
Wei Pu Tan
Keyword(s):  
Short Circuit ◽  
Short Circuit Current ◽  
Stable Operation ◽  
Application Range ◽  
Three Phase ◽  
Different Types ◽  
Calculation Results ◽  
Current Calculation ◽  
Important Significance ◽  
Selection Of

Analysis the important significance of transformer short-circuit current calculation for the stable operation of power system. Lead to three different types of transformer short-circuit current calculation methods, this literature uses a simplified example to compare the characters among three methods. Meanwhile, calculation by using the theory to get a quantitative range of simplified method. The calculation results and theory support each other, finally, summarizing the application range of the three methods, and offering a reference for reasonable selection of short-circuit current methods.

scholarly journals Influence of Different Types of Recombination Active Defects on the Integral Electrical Properties of Multicrystalline Silicon Solar Cells

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Dominik Lausch ◽  
Christian Hagendorf
Keyword(s):  
Solar Cells ◽  
Electrical Properties ◽  
Short Circuit ◽  
Type A ◽  
Crystal Defects ◽  
Process Conditions ◽  
Type B ◽  
Si Solar Cells ◽  
Different Types ◽  
The Impact

In this contribution the influence of different types of recombination-active defects on the integral electrical properties of multicrystalline Si solar cells is investigated. Based on a previous classification scheme related to the luminescence behavior of crystal defects, Type-A and Type-B defects are locally distinguished. It is shown that Type-A defects, correlated to iron contaminations, are dominating the efficiency by more than 20% relative through their impact on the short circuit current ISC and open circuit voltage VOC in standard Si material (only limited by recombination active crystal defects). Contrarily, Type-B defects show low influence on the efficiency of 3% relative. The impact of the detrimental Type-A defects on the electrical parameters is studied as a function of the block height. A clear correlation between the area fraction of Type-A defects and both the global Isc and the prebreakdown behavior (reverse current) in voltage regime-2 (−11 V) is observed. An outlier having an increased full-area recombination activity is traced back to dense inter- and intragrain nucleation of Fe precipitates. Based on these results it is concluded that Type-A defects are the most detrimental defects in Si solar cells (having efficiencies > 15%) and have to be prevented by optimized Si material quality and solar cell process conditions.

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