• Proceedings of the KIEE Conference
• /
• 2006.07c
• /
• pp.1525-1526
• /
• 2006

Electrical current always travels through the minimum resistance path. In this paper, we are studied on the direction and formation of carbonized conductive path according to surface leakage between electrodes. The analysis of characteristics of the arc discharge as surface is broken down between exposed live parts. Using the HSIS(high speed imaging system, 100,000fps, redlake ltd., USA), it took photographs by arc growth mechanism occurred in on/off surge, ground fault and discharge between electrodes. Therefore, it recommended for results of technology development and application such as theoretic verification of an arc direction and economic security according to a technology about connecting arc generation in surfaces of insulators. Hereafter, it expected effects that application of energy utility technology through the arc control.

• Korean Journal of Materials Research
• /
• v.11 no.2
• /
• pp.151-154
• /
• 2001

The leakage current behaviors of PLZT capacitors with top electrodes of Pt, Ir, and $IrO_2$ are investigated before and after hydrogen forming gas anneal. The P-E hysteresis and fatigue properties of Pt/PLZT/Pt capacitors are almost recovered after recovery anneal in $O_2$ ambient. The leakage current mechanisms of PLZT capacitors with Pt and $IrO_2$ top electrodes are consistent with space-charge influenced injection model showing the strong time dependence irrespective of annealing conditions. On the other hand, the leakage current behavior of Ir/PLZT/Pt capacitor shows steady state independent of time because IrPb, conducting phase, formed at interface between Ir top and PLZT is a high conduction path. Teh leakage current mechanism of Ir/PLZT/Pt capacitor is consistent with Schottky barrier model.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.10 no.4
• /
• pp.718-723
• /
• 2006

Optical module plays an important role in the construction of high speed communication network. Laser diode is a component of optical module, and its characteristics are dependent of temperature, so many researches are reported. In this paper, we proposed the electrical equivalent circuit of PBH-LD based on the rate equations. And, the two leakage paths exit outside the active region. One path is converted pn-diode and the other path is converted two transistors using npn-Tr and pnp-Tr. In order to reduce the leakage currents, we observed the dependence of carrier concentrations of current blocking layers using PSPICE simulator.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2009.04b
• /
• pp.21-22
• /
• 2009

We proposed circular AlGaN/GaN schottky barrier diode, which has no mesa structure near the current path. Proposed device showed low leakage current of 10 nA/mm at -100 V while that of the rectangular device was 34 nA/mm at the same condition. Proposed circular AlGaN/GaN SBD showed high forward current of 88.61 mA at 3.5 V while that of the conventional device was 14.1 mA at the same condition.

• Journal of Power Electronics
• /
• v.16 no.1
• /
• pp.153-162
• /
• 2016

Given their structural arrangement, photovoltaic (PV) modules exhibit parasitic capacitance, which creates a path for high-frequency current during zero-state switching of the converter in transformerless systems. This current has to be limited to ensure safety and electromagnetic compatibility. Many solutions that can minimize or completely avoid this phenomenon, are available. However, most of these solutions are patented because they rely on specific and often complex converter topologies. This study aims to solve this problem by introducing a solution based on a classic converter topology with an appropriate modulation technique and passive filtering. A 5.5 kW single-phase residential PV system that consists of DC-DC boost stage and DC-AC H-bridge converter is considered. Control schemes for both converter stages are presented. An overview of existing modulation techniques for H-bridge converter is provided, and a modification of hybrid modulation is proposed. A system prototype is built for the experimental verification. As shown in the study, with simple filtering and proper selection of switching states, achieving low leakage current level is possible while maintaining high converter efficiency and required energy quality.

• Journal of Power Electronics
• /
• v.15 no.5
• /
• pp.1217-1226
• /
• 2015

In a grid-connected photovoltaic (PV) system, the traditional Z-source inverter uses a low frequency transformer to ensure galvanic isolation between the grid and the PV system. In order to combine the advantages of both Z-source inverters and transformerless PV inverters, this paper presents a modified single-phase transformerless Z-source PV grid-connected inverter and a corresponding PWM strategy to eliminate the ground leakage current. By utilizing two reversed-biased diodes, the path for the leakage current is blocked during the shoot-through state. Meanwhile, by turning off an additional switch, the PV array is decoupled from the grid during the freewheeling state. In this paper, the operation principle, PWM strategy and common-mode (CM) characteristic of the modified transformerless Z-source inverter are illustrated. Furthermore, the influence of the junction capacitances of the power switches is analyzed in detail. The total losses of the main electrical components are evaluated and compared. Finally, a theoretical analysis is presented and corroborated by experimental results from a 1-kW laboratory prototype.

• Journal of the Korean Society of Safety
• /
• v.24 no.4
• /
• pp.28-33
• /
• 2009

This study examined the mounting status of cigar lighter receptacles for vehicles and analyzed the tracking phenomenon that occurs when foreign material entered a cigar lighter receptacle to obtain data for the analysis of accident investigation. Regardless of the vehicle's output, cigar lighter receptacles are mounted in a vehicle horizontally, vertically, or at tilting or inclined angle. The tilting type cigar lighter receptacle is much easier to use but current leakage resulting from foreign materials (coffee, beverages, water, etc.) falling into the cigar lighter receptacle may cause a fire to start. This study used a vehicle battery (DC 12V) as a power supply for the tracking test and configured its circuit in the same way as that of an electrical device in a vehicle. The tracking phenomenon that occurred in the standby mode of the vehicle exhibited a fine flame and an irregular occurrence of smoke. While this tracking phenomenon was occurring, the leakage current and the reaching distance of the flame were measured to be approximately 930mA and $20{\sim}50cm$, respectively. It is thought that the resultant flame may ignite toluene, dust, cigarettes, etc. It was observed that as the tracking progressed, the internal metal socket melted and a hole was created, the surface of which was also severely carbonized. In addition, the electrical resistance of the carbonized conductive path was measured to be approximately $30{\Omega}$. It is thought that this much resistance may cause local heating when leakage current flows and could ignite any nearby flammable material.

• Proceedings of the KSR Conference
• /
• 2008.11b
• /
• pp.281-285
• /
• 2008

Corrosion of metallic structures arises when an electric current flows from the metal into the electrolyte such as soil and water. The potential difference across the metal-electrolyte interface, the driving force for the corrosion current, can emerge due to a variety of temperature, pH, humidity and resistivity etc.. With respect to a given structure, a stray current is to be defined as a current flowing on a structure that is not part of the intended electrical circuit. Stray currents are caused by other cathodic protection installations, grounding systems and welding posts, referred to as steady state stray currents. But most often traction systems like railroads and tramlines are responsible for large dynamic stray currents. This type of stray current is generally results from the leakage of return currents from large DC traction systems that are grounded or have a bad earth-insulated return path. This paper investigates the reports, which is made for protecting the electrical corrosion by the DC traction stray current before the construction period.

• Asia pacific journal of information systems
• /
• v.34 no.1
• /
• pp.321-350
• /
• 2024

When a competent employee leaves an organization, the technical skills and know-how possessed by that employee also disappear, which may lead to various problems, such as a decrease in organizational morale and technology leakage. To address such problems, it is important to increase employees' job satisfaction. Due to the advancement of both information and communication technology and social media, many former and current employees share information regarding companies in which they have worked or for which they currently work via job portal websites. In this study, a web crawl was used to collect reviews and job satisfaction ratings written by all and incumbent employees working in nine industries from Job Planet, a Korean job portal site. According to this analysis, regardless of the industry in question, organizational culture, welfare support, work system, growth capability and relationships had significant positive effects on job satisfaction, while time and attendance management, performance management, and organizational flexibility had significant negative effects on job satisfaction. With respect to the path difference between former and current employees, time and attendance management and organizational flexibility have greater negative effects on job satisfaction for current employees than for former employees. On the other hand, organizational culture, work system, and relationships had greater positive effects for current employees than for former employees.

• Proceedings of the KSR Conference
• /
• 2010.06a
• /
• pp.1885-1891
• /
• 2010

Recently metropolitan local governments is actively introducing urban railway's expand and light rail transit as a means of new transport system. DC electricity feeder system operating in the domestic urban railway is typically a feedback circuit consisted of the contact wire and electric railway vehicle via rail. But stray current is to be defined as a current flowing on a structure that is not part of the intended electrical circuit with respect to a given structure. Stray current is generally results from the leakage of return currents from large DC traction systems that are grounded or have a bad earth-insulated return path. At the place where the current leaves the rail and metallic structures, electrolytic corrosion may take place. This paper presents comparison analysis of field test methods based on criteria of electrolytic corrosion protection of buried metallic structures adjacent to DC traction systems.