• The Journal of Korean Institute of Communications and Information Sciences
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• v.21 no.6
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• pp.1596-1603
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• 1996

A single body type of fiber-optic current and voltae sensor using a rare earth doped YIG and a bismuth silicon oxide single crystsl is proposed, which is used for simultaneous measurement of the AC electric current and AC electric voltage over the trasmission lines. Experimental results showed that the fiber-optic current sensor has the maximum 7.5% error within the current range of 0A to 400A, and the fiber-optic voltage sensor has the maximum 0.87% error within the current range of 0V to 400V. The output waveforms of proposed fiber-optic sensor system has a good agreement with output waveforms of conductor current and voltage. Experimental results proved that the output of fiber-optic current sensor is not affected by the electric voltage applied to the fiber-optic voltage sensor, and also, that the output of fiber-optic voltage sensor is not affected by the electric current applied to the fiber-optic current sensor.

• 전기의세계
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• v.30 no.4
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• pp.231-236
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• 1981

It has been known that D.C. breakdown Voltage is lower than A.C. breakdown Voltage in insulatingoil, but there are still many unvivid points at electric conduction in breakdown or under of high electric field. This study measured the electric current-electric field characteristics (I-E characteristics) and the breakdown Voltage under of D.C. electric field of insulating oil using the system of electrodes that are near the Uniform electric field with a result. I can study, electric conduction in area of high electric field depends upon the Schottky effect. The liquidity of breakdown electric field takes place by the local concentration of electric field. The longer gap is and the more electric current is the more breakdown Voltage decreased. There are not almost the change of electric current-electric field characteristics by materials of electrode.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.52 no.8
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• pp.481-485
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• 2003

In electric railway system, potential of rail has been risen, for return-current flows through rail. The magnitude of rising voltage is different to railway feed system, ground admittance of rail and the load current. If rising voltage of rail is large, electric shock can be occurred to passengers and maintenance- worker, In this paper, we estimate the rising voltage of rail in high speed railway system and check the safety to human beings.

• Journal of the Korean Society of Safety
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• v.15 no.2
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• pp.63-69
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• 2000

The constraint conditions are the stator voltage and the stator current to operate the motor in the flux weakening region. The maximum current is limited by the inverter current rating and the machine thermal rating. Given DC link voltage to control the motor in the flux weakening the maximum voltage is determined by considering PWM strategy, dead time, voltage drop of the inverter switching device, and the margin of the voltage for current forcing. In this paper, the new method to determine the available maximum voltage is derived by the quantitative method and by considering the factors of the voltage drop. The proposed method to determine the maximum voltage is very useful to improve the stability of the motor system and to enlarge the speed operation region in the flux weakening operation. Therefore the utility of the maximum voltage is increased.

• 한국초전도학회:학술대회논문집
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• v.11
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• pp.73-73
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• 2001

• Journal of the Korean Society of Safety
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• v.16 no.3
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• pp.53-60
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• 2001

This paper presents a graphical method for hazard assessment of electric shock by safety criteria. For the human body to be safety actual body current should not exceed safety criteria, i.e. allowable body current. The assessment method presented in this paper is based m the safety criteria of the IEEE Standard 80 as well as the IEC 479-1. The hazard can be assessed in terms of alterable touch voltages instead of alterable body current. Thus, the hazard assessment of given electric shock condition is referred to a procedure by which the actual touch voltages are compared with the allowable (safe) touch voltages. Since the IEC 479-1 safety criteria are nonlinear, the graphical method is presented for the hazard assessment. Body current and body voltage are calculated with the allowable touch voltage. A comparison of the safety criteria of two widely accepted standards, i.e. the IEEE Std 80 End the IEC 479-1 is proposed. Also Thevenin equivalent resistance is obtained from electric shock model expressed by two-port earth-grid-foot system. On the basis of calculated results, the allowable touch voltage, the body current and the body voltage we can conduct the hazard or safety assessment and estimate the severity of electric shock.

• Transactions of the Korean hydrogen and new energy society
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• v.21 no.3
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• pp.149-157
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• 2010

The electromagnetic characteristics of FCEVs (fuel cell electric vehicles) are much different from the existing combustion engine cars as well as hybrid, plug-in-hybrid, and pure electric vehicles due to the high voltage/current generated by a fuel cell stack which uses a compressed hydrogen gas reacted with oxygen. To operate fuel cell stack efficiently, BOP (Balance of Plant) is essential. BOP systems are used many not only for motors in water pump, air blower, and hydrogen recycling pump but also inverters for these motors. Since these systems or components are connected by high voltage cables, EMC (Electromagnetic compatibility) analysis for high voltage/current cable is the most important element to prevent the possible electric functional safety errors. In this paper, electromagnetic fields of high current/voltage cable for FCEVs is studied. From numerical analysis results, time harmonic magnetic field strength of high current/voltage cable have difference of 20～28 dB according to phase. EMI result considered ground effect of FECV at 10 m shows difference of 14.5 dB at 30 MHz and 2.8 dB at 230 MHz compared with general cable.

• Corrosion Science and Technology
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• v.18 no.4
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• pp.117-120
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• 2019

Considering the tendency of development of electrification vehicles, development and verification of new evaluation technology is needed because of new technology applications. Recently, as the battery package is set outdoors of an electric vehicle, such vehicles are exposed to corrosive environments. Among major components connected to the battery package, rust prevention of high-voltage cables and connectors is considered the most important issue. For example, if corrosion of high voltage cable connectors occurs, the corrosion durability assessment of using an electric vehicle will be different from general environmental corrosion phenomena. The purpose of this study is to investigate the corrosion mechanism of high voltage cable connectors of an electric vehicle under various driving environments (road surface vibration, corrosion environment, current conduction by stray current, etc.) and develop an optimal rust prevention solution. To improve our parts test method, we have proposed a realistic test method to reproduce actual electric vehicle corrosion issues based on the principle test.

• Fire Science and Engineering
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• v.28 no.3
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• pp.87-91
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• 2014

This paper is aimed to find electrical fire danger for analyzing the characteristics of temperature, current and voltage signals for motor on electric fan. In order to attain this purpose, detected were the temperature, current and voltage signals on electric wire with free (normal state) and locked (abnormal state) motor. For voltage and current signals, voltage signal is no big difference with normal and abnormal states and current signal is higher in abnormal state (highest 309 mA) than the normal state (highest 203 mA). In the case of Temperature signal, the temperature distribution of the motor as a whole is different. It is difference in the case of the normal state $4^{\circ}C$ and the abnormal state $18^{\circ}C$. In particular, most of the electric wiring to the motor of the fan is attached to the fixture of motor back. Considering at allowable temperature ($60^{\circ}C$) of the electric wire could be accelerated to insulation deterioration. The results of this study will be effectively used in analyzing for electric fire and developing the preventive devices of electric fan.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.57 no.3
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• pp.338-342
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• 2008

Hybrid Electric Vehicle(HEV) is driven by an internal-combustion engine and an electric motor. It is a combination of an internal-combustion engine and several electrical equipments which use a high voltage battery, an electric motors, an inverter and others. But there is not any separate detailed enforcement regulations for high voltage electric appliances in the existing vehicle-related safety standards. So, test standards suggestion as well as test technique development need to be done for ensuring electrical safety, for an electric motor, a high voltage battery, a(n) inverter/converter and an electric power transmission units and other equipments to ensure the safety of high voltage electric appliances which is the HEV key electrical component. In this paper, We are to provide helpful data to support test technique development and test standard establishment for HEV design and electrical safety security by the following methods; by measuring the voltage, the electric current, and the frequency of HEV, by analyzing electrical characteristics of high voltage electric appliances, and by analyzing temperature characteristics of the electrical current among the analyzed electrical characteristics by thermal imagining cameras.