scholarly journals Arc Discharge–Induced Ignition of Combustibles Placed on a Damaged AC Power Supply Cord

Energies ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 681
Author(s):  
Kiyoto Takenaka ◽  
Yusuke Ishikawa ◽  
Yukio Mizuno ◽  
Wenyi Lin
Keyword(s):  
Power Supply ◽  
Arc Discharge ◽  
Short Circuit ◽  
Circuit Breaker ◽  
Research Papers ◽  
Ac Power ◽  
Induced Ignition ◽  
Fire Ignition ◽  
Intact Element

One of the major causes of unintentional electrical fires is short circuit of an electrically and/or mechanically damaged alternating power supply cord. Detecting of such an event and interrupting the power supply may be beyond the capability of a conventional electro-mechanical circuit breaker. A lot of research papers have been published related to arc fault of wiring and its detection method. Furthermore, arc fault circuit interrupters have been put into practical use. The objective of the present paper is to understand fault of damaged power supply cord under two selected situations observed in practical use or considered suitable to understand fire ignition. Using two kinds of samples similar to but different from samples prescribed in UL1699 standard, the ignition mechanism of combustibles is discussed based on the results of laboratory experiments. The findings herein underscore the important role of the arc in the ignition of combustibles that are placed on the damaged part of a power supply cord, which is normally followed by a short circuit of broken element conductors or breakage of intact element conductors. Moreover, a possible arc detection feature in the two situations is discussed based on a distorted voltage waveform.

scholarly journals Construction of High Precision AC-DC Power Supply

2020 ◽  
Vol 8 (6) ◽  
pp. 2049-2051
Keyword(s):  
Power Supply ◽  
Short Circuit ◽  
Circuit Breaker ◽  
Specific Load ◽  
Research Facility ◽  
Dc Power ◽  
Ac Power ◽  
Supply Equipment ◽  
Load Regulation ◽  
Efficiency Test

Several accessible power supply equipment with different difficulty levels and complexity mostly give a singular DC output that does not provide same use when an Output AC Power that is quite low to a great extent preferred. In this work, a stabilize, fixed and varying power supply device that has output voltage of 0.5 V to 18.15 V variable DC, and current range from 0 - 0.88 A with short circuit protection was constructed by using inexpensive materials, and fuse was used as circuit breaker . Likewise, we examined the regulation attributes of the power supply units that is just been constructed to a specific load regulation to decide its strength by contrasting it with a regular power supply device and ascertain the power supply's effectiveness through its efficiency. Test and examination were carried out utilizing the developed power supply unit to power loads of 10 to 50 Ω. The trend of the output results demonstrated that the power supply was in line with the standard PSU. The output supplied would be useful in research facility estimation to supply the power for direct incorporated circuits, delicate circuits, simple and advanced circuits, TTL and wide-ranging applications necessitating supply force.

The Design of Marine 24 V DC Uninterruptible Power Supply

2014 ◽  
Vol 536-537 ◽  
pp. 1537-1541
Author(s):  
Juan Xiao
Keyword(s):  
Power Supply ◽  
Short Circuit ◽  
Battery Management ◽  
Single Chip ◽  
Uninterruptible Power Supply ◽  
Management Scheme ◽  
Ac Power ◽  
Actual Use ◽  
Emergency Power ◽  
Uninterruptible Power

A marine DC uninterruptible power supply is designed. The UPS adopts PIC16C73 single-chip microcomputer to realize the battery management. Both AC power and battery power, the output voltage stability in 23 to 24 v.Via advanced battery management, two sections of charging, equalized charging and floating charging can automatic convert and the DCUPS has many functions of protection, such as over-voltage protection ,under voltage protection and short circuit protection.The actual use on the ship and other occasions showed that the DCUPS is convenient and practical,and is more simple, reliable and longer emergency power supply than the traditional AC-DC uninterruptible power supply management scheme.

Development of an Automated Three-Phase Distribution Box System

2017 ◽  
Vol 6 (2) ◽  
pp. 233 ◽  
Author(s):  
N M Nor ◽  
N S Zemri ◽  
S A Daud ◽  
T Ibrahim ◽  
H Daud
Keyword(s):  
Power Supply ◽  
Fault Location ◽  
Phase Distribution ◽  
Short Circuit ◽  
External Disturbance ◽  
Circuit Breaker ◽  
Critical Issue ◽  
Power Outage ◽  
Three Phase ◽  
Continuous Power

Most electrical appliances require continuous power supply. For domestic use, crucial appliances such as refrigerator, aquarium and alarm system highly depend upon the continuity of power supply. However, if they are left without electricity due to power outage or blackouts caused by internal or external disturbance, the discontinuity of power supply could be a critical issue to some involving party. Blackouts may be due to short circuit, fault or the overloading of electricity mains. During power outage, Residual Current Device (RCD) detects fault currents from live to the neutral wire within circuit and will trip to prevent shock. This circumstance can increase safety when a house is left unoccupied. Be that as it may, the power will remain switched off until manually reset by man. Thus, this paper presented a new concept of Three-Phase distribution box system in order to overcome tripping problem. This system will be able to identify and isolate the fault using measurement of current flow into each Miniature Circuit Breaker (MCB) of appliances and current flowing out from each of the load. The measured current value will be compared and the maximum allowable difference is 30mA. If the current difference exceeds the maximum limit then the fault MCB will be detected. Hence RCD will be automatically close the circuit after determining the fault location via the motor operation to make sure of power stability and evade any property loss.

scholarly journals A new algorithm for automating power supply of an AC traction network with a sectioning points on switches

2017 ◽  
Vol 76 (5) ◽  
pp. 266-272
Author(s):  
L. A. German ◽  
A. Yu. Popov ◽  
A. V. Samorukov ◽  
D. V. Ishkin ◽  
D. V. Yakunin ◽  
...  
Keyword(s):  
Power Supply ◽  
Short Circuit ◽  
Circuit Breaker ◽  
Contact Network ◽  
Successful Operation ◽  
Traction Substation ◽  
Traction Network ◽  
Long Time ◽  
Traction Substations ◽  
Automatic Reclosing

The article considers modern sectioning points on contact network and determining the location of the damage, imthe switches, which differs by the introduction of new functions for plemented in the IntTer smart terminal. These new functions are determining a stable (or passing) short circuit in the disconnected deciding whether to perform a quick automatic restart of the circuit breakers after an emergency shutdown or finding the fault zone without testing the insulation of the contact network. The principle of operation of the functions under consideration is analyzed in the article. The limits of the optimum time of the current-free pause of the circuit breaker for automatic re-activation (AR) for each inter-substation zone are established. The paper describes the existing algorithm for automating power supply of an AC traction network (the normal reclosing algorithm) and indicates the unfavorable consequences from its application, in particular, related to the long time of the absence of voltage in the contact network. It was noted that the decision to reduce the voltage recovery time performed by introducing the function of determining the passing (or stable) short-circuit in the switched-off contact network in traction substations is due to the cost of additional high-voltage equipment and requires a rethinking. Thus, a new algorithm for automating the power supply of the traction network (the BAR algorithm) is presented, which is quite easily implemented at the modern sectioning post, which has voltage transformers for each supply line of the contact network, in contrast to the supply lines of the substation contact network and is caused by the transfer of the function of determining the passing (or steady ) short circuit to the sectioning point. In the article, the issue of performing the automatic reclosure of the power line of the traction substation is considered dependent on the successful operation of the BAR algorithm of the sectioning point. It is established that the most rational option is the implementation of a dependent automatic reclosing of a traction substation using telemechanics. The authors analyze the possibility of manufacturing compact sections of the ac contact network on the basis of single-phase re-closers OR-27.5 kV. It is noted that it is advisable to use a new automation scheme in conjunction with the sectionalization points on reclosers.

scholarly journals Development of Fast Acting Electronic Circuit Breaker

2020 ◽  
pp. 149-152
Author(s):  
K. Siva Shankar ◽  
D. Gayatri ◽  
Ganesh B ◽  
T. Ramarao ◽  
N. Sai Kumar ◽  
...  
Keyword(s):  
Power Supply ◽  
Electronic Circuit ◽  
Short Circuit ◽  
Circuit Breaker ◽  
Electrical Energy ◽  
Operational Reliability ◽  
Current Transformer ◽  
Short Period ◽  
In Series ◽  
Fast Acting

The rapid increase in population has more demand and consumption of electrical energy in the market, use of equipments such as electrical and electronic components are also costlier. In order to protect the system from overload, or short circuit here is one possibility, which is by fast acting electronic circuit breaker. A circuit breaker is an automatically operating switch designed to shut down the power supply when it is overloaded. The tripping depends on the current passing through the CT’s which is connected in series with load. The project is designed to develop the power supply which shuts down when it is overloaded by using a fast acting electronic circuit breaker. The concept of developing a electronic circuit breaker came into focus realizing that the conventional circuit breakers such as MCB’s and fuse take longer time to trip. Therefore for sensitive loads it is very important to activate the tripping mechanism within short period of time. We know that the Modern technologies are paramount to provide operational reliability and financial profitability, so it is very important to develop an electronic circuit breaker by using a micro controller arduino. Here an electronic circuit breaker is designed using arduino in which program is dumped and a particular is set so that the system can shut down when it is overloaded. Here the voltage is sensed and rectified to DC and then it is compared with a preset voltage by a level comparator to generate an output that drives a relay to trip the load. The relay is preferred in place of semiconductors because such solid state switches would invariably fail in case of accidental short circuits. This project is designed to overcome the drawback of thermal type of circuit breaker like MCB based on a thermal bimetal lever trip mechanism which is very slow. This project is based on the current sensing across a series element typically a CT (Current Transformer). The current sensed which is compared against the preset value proportional to the voltage by comparator which is inbuilt in arduino to generate an output that drives a relay to trip the load very fast.

scholarly journals Pinched Power Cord is Latent Defect Causing Fire When Appliance Is Not in Use

2021 ◽  
Vol 38 (1) ◽  
Author(s):  
Mike Leshner
Keyword(s):  
Power Supply ◽  
Direct Evidence ◽  
Low Voltage ◽  
Short Circuit ◽  
Circuit Breaker ◽  
Cause Analysis ◽  
Expert Opinions ◽  
Design Defect ◽  
Scientific Principles ◽  
Witness Statements

After a fatal residential fire, witness statements and burn patterns pointed investigators toward an electrically powered upholstered reclining chair as the origin. A search for exemplar recliners identified slightly different designs of the power supply, which converts house current to low-voltage direct current for driving the motor. Although the fire left no direct evidence of its cause, analysis of unburned exemplars uncovered a design defect in the power supply electrical enclosure design, causing damage to the power cord during assembly. The transformer was found to press against the two-conductor power cord, in a location inside the unit that was concealed after assembly. The newer units did not have this design defect. Investigators developed the hypothesis that over time, the sustained force of the transformer against the cord enabled the insulation to deform such that a short circuit occurred in the power cord and caused the fire — even when the recliner was not in use and if the house wiring circuit had been protected by a circuit breaker. This paper details the investigation, testing, and findings, including dissenting expert opinions. More importantly, it shows how forensic engineers conduct detective work and apply scientific principles to achieve useful results.

scholarly journals Electrical Device Protection from Overvoltage in a DC Power Supply Network: Fast-acting Protection, Realized by an “Artificial” Short Circuit in the Input of the Protected Device

2020 ◽  
Vol 10 (1) ◽  
pp. 5314-5319
Author(s):  
S. K. Filipova-Petrakieva ◽  
Y. M. Shopov
Keyword(s):  
Power Supply ◽  
Supply Voltage ◽  
Classical Method ◽  
Short Circuit ◽  
Circuit Breaker ◽  
Supply Network ◽  
Power Supply Voltage ◽  
Dc Power ◽  
Dc Power Supply ◽  
Fast Acting

In the present paper a protective device based on the so-called “artificial” short circuit in the input of the network, is proposed. To ensure the necessary time for switching on the protection, the increased power supply voltage is delayed to reach in the input of the protected device by additional inductance L, which is connected in series to the power supply. As a result of this forced short circuit, the DC-power supply is switched off by a standard protective circuit-breaker. The short circuit is realized by a fast-acting semi-conductor device (e.g. diac + thyristor, etc.). The controlling signal is formed as a voltage across a capacitor that is a part of RC-circuits connected in parallel to the DC-power supply network. An analytical expression for this voltage, using a classical method for transient analysis, is obtained. The main aim is to determine the exact time of switching on the protection. The research is confirmed with simulations by OrCAD PSpice under the exact values of the elements in the RC-circuits considered. Two rapid increase cases in the power supply voltage are considered: positive jump and linear increase. The suggested solution is applicable for overvoltage protection of different electrical devices. The electrical scheme, based on the electronic components, ensures a fast-acting breaking, which guarantees secure protection. Based on the analytical expressions, the synthesis of the circuit for control and protection is made and the respective values of its elements are calculated.

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