• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.24 no.2
• /
• pp.133-141
• /
• 2010

Grounding system insures a reference potential point for electric devices and also provides a low impedance path for fault currents in the earth. The ground impedance as function of frequency is necessary for determining its performance since fault currents could contain a wide range of frequencies. Copper and concrete rod electrodes are the most commonly used grounding electrode in electric distribution systems. In this paper, the ground impedance of copper and concrete rods has been measured by frequency and time domain characteristic tests. An equivalent transfer function model of the ground impedance is identified from the measured values by using ARMA method and evaluated by comparing conventional grounding impedances.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.24 no.2
• /
• pp.69-76
• /
• 2010

Recently, the natural environment changes drastically and the frequency of occurrence for lightning has gradually been increased. Such lightning delivers high volume of energy along the power line and communication line to the equipment in use. The high volume of energy arising from the lightning surge develops in fast velocity to destroy the facilities in power source and many other facilities in operation in sequential destruction with vast energy. This paper examines the characteristics of ZnO varistor to prevent from thermal runaway. We carry out performance evaluation of electrical characteristics on ZnO varistor. we will develop ZnO varistor Prevented from thermal explosion using test result of this paper.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.23 no.4
• /
• pp.29-38
• /
• 2009

The GHP(Gas Heat Pump) is an efficient cooling;11eating system in which a compressor is driven by a gas engine and is brodening its application to the facilities such as schools and office buildings. It is difficult to control the GHP system because of slow response, big time constant and time variant system. These nonlinear loads generate harmonic currents and create distortions on the sinusoidal voltage of the power system Harmonic field measurements have shown that the harmonic contents of a waveform varies with time. A cumulative probability approach is the most commonly used method to solve time varying harmonics. This paper provides an in depth analysis on harmonics field measurement of the GHP loads, harmonic assessment by me 61000-3-2, and harmonic simulation and harmonic filter application using EDSA program for the case study system.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.17 no.6
• /
• pp.130-137
• /
• 2003

Because of falling-off in power quality by harmonics, obstacles like lowering of capability, noise, vibration of power facilities and so on are occurred. Also generation of harmonics is inevitable and the point at harmonics is seriously gathering strength because energy saving installation using semiconductor circuit as countermeasures to enhance energy efficiency will be broadly spread and the use of energy conversion equipment like motor speed control contrivance, energy keeping installation and so on will increase, in the future. In order to eliminate harmonics obstacle, precision measurement and analysis on voltage, current, power factor, the each ingredient of harmonic order, the percentage of total harmonic distortion, and so forth are needed. In this paper, we developed low-cost measurement system to measure and analyze power quality connected with harmonics and verified it's performance by measuring and analyzing power quality in the three-phase and four-wire system.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.14 no.3
• /
• pp.88-96
• /
• 2000

The instantaneous power theory have been considered as efficient theory in recent years, because it is easier to understand numerical representation and more soft to control PWM power converter on $\alpha$-$\beta$ stationary reference frame. From the forgoing theory, with regard to the calculating process of compensating reference current, there are many induced components of current/ power, and these components have consequently influence on physical interpretation of instantaneous power theory. Especially, beginners for studing the instantaneous power theory don't have enough informations for standard waveform of induced $\alpha$-$\beta$ components. Therefore, this paper describes simulation works using MATLAB/SIMULINK for $\alpha$-$\beta$ space trajectories and waveforms of $\alpha$-$\beta$ current and power components, induced from the instantaneous power theory. It is respected that the results in this paper are serviceable as basic information to assist beginner for studing the instantaneous power theory.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.20 no.8
• /
• pp.36-41
• /
• 2006

Computer Loads can be found in all of modern society. The switching mode power supplies used in personal computers are major sources of harmonic currents. Harmonic currents can cause lots of harmonic problems such as disruption in computer performance. A series resonant filter is very effective in harmonic reduction for personal computer loads. Voltage sags are short duration reductions in rms voltage. The main causes of voltage sags at faults, motor starting, and transformer energizing. Personal computers are another example of devices sensitive to voltage sags. A serious voltage sag at the terminals way lead mis-operation of the equipment. This paper presents an in depth analysis to evaluate the effect of harmonics reduction based on the IEC 61000-3-2 and the effect of voltage sag using ITI curve by applying a series resonant filter for personal computer loads.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.23 no.10
• /
• pp.143-150
• /
• 2009

The bar-shaped electrode is very popular in earth construction for its easy obtainments of the regulative grounding resistance values on power distribution systems in many countries. For these reason, a lots of researches are being proceeded on its deformation and materials. But the grounding construction has limit for improvement the grounding resistance characteristics not only by the improvement of the driven electrode, because that the grounding characteristics are very sensitive to soils(hard, soft). This study is about the construction methods on which the driven electrode can be serially or parallely connected using by hollow screw rod for obtaining the regulative grounding resistance values. The experimental results show that the grounding resistance values are reduced more than 30[%] comparing with the other construction methods under the same conditions(earth resistance, numbers of driven electrode, construction method of serial and parallel, chemicals for reducing grounding resistance, water).

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.21 no.1
• /
• pp.35-41
• /
• 2007

Recently, there are increasing social needs for stable supply of electric power and securing high quality of information and communication services. In this work, to propose the effective protection countermeasures of information-oriented equipments against lightning surges, the protection effects of surge protective devices(SPDs) were experimentally investigated using actual-sized test circuits in various installation conditions. As a result, it was found that the protection effect of SPDs is quite different depending on the factors, such as the grounding system of power source, numbers of branch circuits, wiring method of grounding leads, and etc. In case of installing SPDs for information-oriented equipments, including all electric power lines and communication lines, the common grounding should be the most effective. Wiring method containing grounding leads with power lines in metal conduit is suitable to improve the surge cutoff performance of SPDs.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.21 no.1
• /
• pp.75-81
• /
• 2007

This paper dealt with the design and implementation of an expert system to monitor and diagnose the lightning arresters in GIS substations. The expert system consists of a data acquisition module(DAM) based on microprocessor and diagnostic algorithms. The DAM measures and analyzes several parameters necessary for the arrester diagnosis such as system voltages, leakage current components, and temperatures. Also, it includes an intelligent surge counter which can record the date and tin, the polarity, and the amplitude of surge currents. All the data acquired is transmitted to a remote computer by a low rate wireless network specified in IEEE 802.15.4 to avoid electromagnetic intereference under high voltage and large current environments. The decision-making for the arrester diagnosis completes with a Java Expert System Shell(JESS) which is composed of a knowledge base, an inference engine and a graphic user interface(GUI).

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.22 no.2
• /
• pp.114-119
• /
• 2008

With the improvement of industrial society, the high quality electrical energy, simplification of operation and maintenance, ensuring reliability are being required. We request urgently change a $SF_6$ for an environment friendly gas insulation material. In this paper the experiments of breakdown characteristics by pressure and gap change of Imitation-Air in model GIS(Gas Insulated Switchgear) were described. Also assess of breakdown characteristics about Imitation-Air and $SF_6$. It is considered in this paper that the results are fundamental data for electric insulation design of Distribution Power Facilities which will be studied and developed in the future. The pressure to be confronted to $SF_6$ gas 1[atm] for Distribution Power Facilities is Imitation-Air 3[atm]. And we could make an environment friendly gas insulation material with maintaining dielectric strength by Imitation-Air which generates a lower level of the global warming effect.