• 전기학회논문지P
• /
• 제59권4호
• /
• pp.473-476
• /
• 2010

In this paper, we analyzed the short circuit current of a low voltage direct current distribution system. For the analysis, we performed the modeling of the low voltage direct current distribution system with a 6-pulse three-phase thyristor rectifier using the PSCAD/EMTDC, surveyed impedance of sources, transformers and distribution lines to run a simulation. A result of the simulation is that short circuit currents of the direct current distribution system with the rectifier decreased due to a thyristor-ON-resistance(Ron). But in case of the low thyristor-ON resistance, output fault current of the rectifier increased over three-phase short circuit current of an AC power system without a rectifier by regular ratio of the rectifier. Because the output fault current of the rectifier can increase over interrupting the capacity of circuit breakers, studying short circuit currents of a low voltage direct current distribution system with a rectifier is necessary for introducing the direct current distribution systems.

• 대한전기학회논문지:전력기술부문A
• /
• 제48권6호
• /
• pp.807-814
• /
• 1999

In this paper, it is shown that high frequency current can be controlled to concentrate near the desired path in a conducting plate. A conducting plate is modelled to examine current distribution. And current distribution is analyzed in view of the frequency and geometric characteristics of current path. The high frequency current behavior from the analysis is compared with the experiments. The results, obtained by the experiments of test specimens, are in good agreement with the analytical results.

• 한국초전도ㆍ저온공학회논문지
• /
• 제19권1호
• /
• pp.26-29
• /
• 2017

We studied the distribution of the current density and its magnetic-field dependence in GdBCO coated conductors with AC bias currents using low temperature scanning Hall probe microscopy. We selectively measured magnetic field profiles from AC signal obtained by Lock-in technique and calculated current distributions by inversion calculation. In order to confirm the AC measurement results, we applied DC current corresponding to RMS value of AC current and compared distribution of AC and DC transport current. We carried out the same measurements at various external DC magnetic fields, and investigated field dependence of AC current distribution. We notice that the AC current distribution unaffected by external magnetic fields and preserved their own path on the contrary to DC current.

• 한국초전도ㆍ저온공학회논문지
• /
• 제14권2호
• /
• pp.16-19
• /
• 2012

The influence of current distribution on the transport current loss in vertically stacked high-$T_c$ superconductor (HTS) tapes was evaluated. AC loss was analyzed as a function of current distribution by introducing a current distribution parameter through a numerical method (finite element analysis). AC loss under non-uniform current distribution is always higher than that for a uniformly distributed transport current in a conductor. Although the effect of non-uniformity is relatively insignificant in low transport current, AC loss increases substantially in high transport current regions as non-uniformity is enlarged. The results verify that non-uniform current distribution causes extra loss by examining the cross-sectional view of current densities in stacked conductor.

• 소성∙가공
• /
• 제13권3호
• /
• pp.279-284
• /
• 2004

Electroforming is the highly specialized use of electrodeposition for the manufacture of metal parts and basically a specialized form of electroplating. So, we can apply electrochemical system analysis for electroforming process. Electrochemical systems are concerned with the interplay between electricity and chemistry, namely the measurements of electrical quantities, such as current density, potential, and charge, and their relationship to chemical parameters. This paper based on the basic equations of electrics and electrochemical kinetics, was employed for a theoretical explanation of the current density distribution on electroforming process. We calculated current density distribution and potential distribution on cathode. Also, calculated current density distribution of vertical direction. It was shown that current density is related with distance of between anode and cathode and mass transfer process.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2011년도 제42회 하계학술대회
• /
• pp.67-68
• /
• 2011

This paper analysed a protective equipment in power distribution system linked distribution power system when a superconducting fault current limiter(SFCL) is installed. This paper focused on a recloser, because the recloser is a general protective equipment. When power distribution system linked distribution power system, a fault current is increased by adding fault current of distribution power system. The increased fault current makes many problems. But SFCLs are limiting fault current and help the protective equipment to operate normal process. We analysed the operation of protective equipment in power distribution system linked distribution power system with SFCLs.

• 조명전기설비학회논문지
• /
• 제27권7호
• /
• pp.37-44
• /
• 2013

Phase to ground faults are possibly one of the maximum number of faults in power distribution system. During a ground fault the maximum fault current and neutral to ground voltage will appear at the pole nearest to the fault. Distribution lines are consisted of three phase conductors, an overhead ground wire and a multigrounded neutral line. In this paper phase to neutral faults were staged at the specified concrete pole along the distribution line and measured the ground fault current distribution in the ground fault current, three poles nearest to the fault point, overhead ground wire and neutral line. A simplified equivalent circuit model for the distribution system under case study calculated by using MATLAB gives results very close to the ground fault current distribution yielded by field tests.

• Journal of Electrical Engineering and Technology
• /
• 제1권3호
• /
• pp.308-312
• /
• 2006

The inductance difference between conducting layers of high-Tc superconducting (HTSC) power transmission cable causes the current sharing of each conducting layer to be unequal, which decreases the current transmission capacity of HTSC power cable. Therefore, the design for even current sharing in HTSC power transmission cable is required. In this paper, we investigated the current distribution of HTSC power cable with a shield layer dependent on the pitch length and the winding direction of each layer. To analyze the effect of the shield layer on the current sharing of the conducting layers of HTSC power cable, the current distribution of HTSC power cable without a shield layer was compared with the case of HTSC power cable with a shield layer. It could be found through the analysis from the computer simulations that the shield layer of HTSC power cable could be contributed to the improvement of current distribution of conducting layers at the specific pitch length and the winding direction of conducting layer. The result and discussion for the current distribution calculated for HTSC power transmission cable with a shield layer were presented and compared with the cable without a shield layer.

• 한국초전도ㆍ저온공학회논문지
• /
• 제1권2호
• /
• pp.20-24
• /
• 1999

The study of HTS(High Temperature Superconducting) bulk in magnetic levitation system requires the calculation of currents distribution in HTS bulk is very important to determine this forces. We have made computer program to find this current distribution and levitation force. J-E relation in HTS bulk is extremely nonlinear, so iteration method must be used to determine the current distribution. We developed the method to determine the current distribution in the unifrom-field model and, using this method, calculated the levitation force in permanent-magnet-levitation model.

• 한국초전도저온공학회:학술대회논문집
• /
• 한국초전도저온공학회 2000년도 KIASC Conference 2000 / 2000년도 학술대회 논문집
• /
• pp.29-32
• /
• 2000

Superconducting transmission cable is one of interesting part in power application using high temperature super-conducting wire as transformance. One important parameter in HTS cable design is transport current distribution because it is related with current transmission capacity and loss. In this paper, we present the calculation theory of current distribution for multi-layer cable using the electric circuit model and in example, calculation results of current distribution and AC loss in each layer of 4-layer HTS transmission cable.