• Proceedings of the KIEE Conference
• /
• 1996.07b
• /
• pp.850-852
• /
• 1996

High impedance fault (HIF) is defined as fault that general overcurrent relay can't detect or interrupt, Especially when HIF occur under 15 kV, energized high voltage conductor results in fire hazard, equipment damage or personal threat. Because most HIF occur arc, HIF detection using arc is to increase. Numerical arc model can be applied in an electromagnetic transients program (EMTP) to reproduce the dynamic and random characteristic of arcs for any insulator arrangement, current and system voltage. It allows the representation of any network configuration to be investigated, so the digital simulation of arc faults through air can be substitute for demanding power arc test.

• Proceedings of the KIEE Conference
• /
• 2000.07a
• /
• pp.366-368
• /
• 2000

When faults occur in transmission lines, the classification of faults is very important. If the fault is HIF(High Impedance Fault), it cannot be detected or removed by conventional overcurrent relays (OCRs), and results in fire hazards and causes damages in electrical equipment or personal threat. The fast discrimination of fault needs to effective protection and treatment and is important problem for power system protection. This paper proposes the fault detection and discrimination algorithm for LIFs(Low Impedance Faults) and HIFs(High Impedance Faults). This algorithm uses artificial neural networks and variation of 3-phase maximum currents per period while faults. A double lines-to-ground and line-to-line faults can be detected using Neural Network. Also, the other faults can be detected using the value of variation of maximum current. Test results show that the proposed algorithms discriminate LIFs and HIFs accurately within a half cycle.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.14 no.6
• /
• pp.1447-1452
• /
• 2010

Ubiquitous society to build basic infrastructure in the power supply and power equipment safety is important. u-City in order to prevent the disaster of u-IT Power Equipment Performance Module and the security for the safety of the u-City is necessary. In this paper, the power unit of u-IT module, temperature sensor, humidity sensor, equipped with sensors arranged throughout the fire, and home distribution boards, Home Network Wall-Pad, Blocker, MPNP black boxes, arc detection, arc safety equipment, outlet of the modular performance evaluation methods and security methods will be studied. u-IT power devices and sensors to analyze the information conveyed by proactive risk and ensure safety, access control, authentication, security safeguards, such as u-IT integrated management system for electrical safety and strengthen the security, safety and security with a u-City will contribute to the construction and operation.

• Journal of Advanced Marine Engineering and Technology
• /
• v.34 no.2
• /
• pp.332-338
• /
• 2010

Annually, electrical fires caused by arcing phenomena in power system rapidly increase as the use of more electric appliances, but there is no established method for the prevention of the accidents. With this background, this paper dealt with the experimental results on a series arc detection technique and a device for air conditioners. Series arcing phenomena that is generated in incomplete connection of air conditioners was simulated, and the frequency spectrum was analyzed. The Fast Fourier Transform (FFT) of the arc pulse showed that the dominant frequency components exist in ranges of 190 kHz~250 kHz and 900 kHz~1.6 MHz. An arc detection circuit with low cut off frequency of 170 kHz to attenuate 60 Hz by 170 dB and a signal discriminator were designed. Also, an algorithm which separate series arc signal from unwanted noises produced by switching operation, inverter, and surge was proposed. Application experiment was carried out on several types of air-conditioners by using the arc generator specified in UL1699, and the results showed the over 99 % accuracy.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2010.05a
• /
• pp.307-310
• /
• 2010

Ubiquitous society to build basic infrastructure in the power supply and power equipment safety is important. U-City in order to prevent the disaster of U-IT Power Equipment Performance Module and the security for the safety of the U-City is necessary. In this paper, the power unit of U-IT module, temperature sensor, humidity sensor, equipped with sensors arranged throughout the fire, and home distribution boards, Home Network Wall-Pad, Blocker, MPNP black boxes, arc detection, arc safety equipment, outlet of the modular performance evaluation and security measures will be studied. U-IT power devices and sensors to analyze the information conveyed by proactive risk and ensure safety, access control, authentication, security safeguards, such as U-IT integrated management system for electrical safety and strengthen the security, safety and security with a U-City will contribute to the construction and operation.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.19 no.3
• /
• pp.624-629
• /
• 2018

The current study was conducted to develop a portable composite gas detector allowing the detection of both $CO_2$ and $CH_4$ gases by means of the Non Dispersive Infra-Red (NDIR) method. The gas detector is configured to radiate infrared waves using infrared lamps, where the wavelength of the infrared light is reduced due to absorption throughout the chamber, and this reduction (absorption) is detected by the absorption detector, before being converted and amplified to a 3.5V~6V electrical signal, providing as accurate a measurement as possible. The conventional singe sensor method measures the relative measurement by absorbing only specified wavelengths of infrared radiation, which in the case of gas detection leads to problems with accuracy due to the lack of a reference sensor when detecting light with a wavelength of only $4.26{\mu}m$. The dual sensor employed in this study provides a comparative measurement between the reference value derived from the wavelength of $3.91{\mu}m$, which is not influenced by other gas sources, and the measurement value derived from the wavelength of $4.26{\mu}m$, in order to reduce the errors and enhance the reliability, thereby allowing low power consumption for portable devices and multi-gas detection for both $CO_2$ and $CH_4$ gases. The portable composite gas detector developed herein provides a measurement rage of 0ppm~5,000ppm for $CO_2$ gas, and 0.5%vol for $CH_4$, which allows the determination of whether the $CO_2$ and $CH_4$ contents in indoor air are less than 1,000ppm or not. The current study established that the composite gas detector can be interlinked with firefighting appliances through portable devices or home automation, and is anticipated to be very effective in fire prevention.