• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.11a
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• pp.319-320
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• 2005

This paper describes the principles and structures of an expert system for arrester diagnosis. The expert system analyzes and decides the arrester condition by total leakage current, its harmonic component, and temperature because the deterioration of arresters appeared in an increase of leakage current and surface temperature of it. Additionally, influence of system voltage harmonics and ambient temperatures on leakage current changes were considered in the design. The expert system is consisted of a data acquisition module and a computer for monitoring. The acquired analog data are digitalized and transmitted to the computer by an optical link which is free from interference.

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

• The Transactions of The Korean Institute of Electrical Engineers
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• v.63 no.12
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• pp.1726-1731
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• 2014

This paper shows the developed new lightning arrester LCM (Leakage Current Measuring device) which is important element of GIS (Gas Insulated Switchgear) Preventive & Diagnostic system and verify its performance though strengthened test standards. The existing lightning arrester LCM was modified to solve measuring errors which happened frequently. At first, we explained the principle of measuring leakage current. Through analyzing some problems which the existing LCM have. we got some improvable items. For the performance verification of the improved LCM, we manufactured prototype LCM which is applied some improvable items such as improving LCM circuit, adding protection circuit, optimizing inner structure of LCM and changing ground design. After then we carried out the performance test. Accredited testing laboratory carried out the performance verification test according to performance test criteria and procedure of reliability test standards, IEC-60225, 61000 and 60068 etc. We confirmed the test results which correspond with the performance test criteria. Also, we confirmed the performance of the improved LCM installed & being operated at G Substation through the immunity test against the normal noise and open/close surge etc.

• Proceedings of the KIEE Conference
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• 2006.07c
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• pp.1465-1466
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• 2006

The monitoring and diagnosing technique for lightning arresters is important to assure the reliability of power supply in GIS-substation. In this paper, we described the implementation of an expert system for GIS arrester facilities. The proposed system consists of a data acquisition module (DAM), a wireless communication module, and a personal computer. The DAM detects system voltages, total leakage currents and its harmonic components, and includes an algorithm to calculate the resistive leakage current by the principle that the magnitudes of resistive leakage current are equal at the same level of the system voltage applied to the arrestor. Also, we designed a surge event detection circuit which can acquire the date, the polarity, and the amplitude of surge events. All the acquired data are transmitted after correction by many algorithms to the remote station through the ZigBee protocol. The expert system is based on the Jave Expert System Shell (JESS) and make more reliable decision by using an exclusive inference process.

• Proceedings of the KIEE Conference
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• 2003.07a
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• pp.561-563
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• 2003

This paper deals with simulation of lightning overvoltage generated by back flashover entering 345[kV] Gas Insulated Substation. In order to protect the substation equipment against lightning surge, insulation coordination is performed with the lightning arrester. This paper suggests optimal location of lightning arrester using the EMTP/ATPDraw to mere economically and effectively reduce the lightning surge incoming overhead lines.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.51 no.1
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• pp.22-30
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• 2002

ln this paper, it was reported the developed results of the monitoring unit for 72.5kY GIS which it is one part of the monitoring system for the substation that Korea Railway Company is promoting. In order to monitor the operational status of GIS, four parameters were chosen: the number of times of the circuit breaker switching, tightness of the gas-sealed units (circuit breaker / disconnecting switch / earthing switch), the number of times of the lightning arrestor operating and the leakage current of the lighting arrester. We constructed the monitoring system that can be judged the operating condition of the GIS from the signal of the suitable sensor for the purpose. Therefore, it is possible to on line monitoring for the condition of the GlS without efforts of the Periodic inspection.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.07b
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• pp.890-893
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• 2002

Since 1970s, varistors using metal-oxide resistors have been applied to Gapless surge arresters for power system. In the paper, the structure of metal-oxide surge arresters without gaps for 362kV GIS which is developed the first in korea has been introduced. And the main evaluation items for the metal-oxide resistors which are reference voltage test, residual voltage test, long duration current impulse withstand test and operating duty test is tested and evaluated.

• Progress in Superconductivity and Cryogenics
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• v.14 no.1
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• pp.20-24
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• 2012

This paper proposes an insulation coordination and surge arrester design for superconducting power system with SFCL(Superconducting Fault Current Limiter) in Icheon substation. In the aspect of the economic analysis, since the superconducting devices are very expensive, the insulation coordination to prevent the dielectric breakdown caused by the lightning surge should be considered carefully. In this paper, the insulation coordination for real grid including SFCL and the design of the protection devices against lightning surge is verified using PSCAD/EM TDC.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.26 no.10
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• pp.95-101
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• 2012

Typically, large scale power generation facilities are linked to 345kV transmission line through a step-up transformer. If the value of transient voltage by generating lightning stroke is large more than electric equipment's BIL, devices insulation is destroyed. LA(Lighting Arrester) is used as a main means of prevention. However, the installation of LA takes the constraints of installation place and expensive installation costs. Therefore, we need to carefully study whether installation of installation can be omitted and the most efficient place of installation. In this paper, we simulated the transient voltage detected by lightning stroke at each equipments in the 345kV transmission power grid by using EMTP-RV program.