• The Transactions of the Korean Institute of Electrical Engineers C
• /
• v.53 no.3
• /
• pp.149-156
• /
• 2004

This paper deals with the effective protection method for the household electric appliances against lightning surges invading from the Power lines. Direct or induced lightning is the main cause of the breakdown of household electric appliance. The most effective protection method is to install SPDs(surge protective devices) at household electric appliances. If SPDs were not installed at most household electric appliances, it is necessary to install SPDs on the mains. Therefore the propagation aspect and protection methods of lighting surges coming into household electric appliances through the mains was experimentally investigated. The in actual-sized test circuits results of protection method for 8 household electric appliances including computer monitors and TV set could be summarized as follows: The breakdown characteristics of household electric appliances from lightning surges were significantly changed with the their input impedance. Namely, the types of input impedance are classified into infinite, resistive or inductive impedances. Especially, the monitor for computer with inductive input impedance from lightning surges was relatively weak against lightning surges. It was confirmed that the self inductance of branch circuits on the mains have protection effect for household electric appliances against lightning surges invading from the power lines. Also the varistors installed at cabinet panel or circuit-breaker were more effective than multi-tap outlet with varistors. When installed varistors in cabinet panel and multi-tap outlet together, the surge protection effect is much more excellent in technical and economical aspects.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.26 no.12
• /
• pp.21-27
• /
• 2012

Korean Industrial Standards for lightning protection system complies with IEC standards. However, the standards are applicable only to buildings and structures more than 20 meters in high. Therefore, it is necessary to determine whether lightning protection system should be installed on structures lower than 20 meters high. This paper proposes an efficient method of assessing risk against lightning of structures lower than 20 meters high. The method suggests simplified lightning protection system and provides selecting an appropriate protection level. The suggested method assumes that structure under assessment has no lightning protection system and there is no person around the structure at the moment of lightning stroke. A simplified method of assessing the risk to human within the structure is developed by adopting the general assessment factor. The selection of a protection level is possible by comparing tolerable risk with physical damage risk caused by a direct lightning. Finally, this paper gives ways to establish surge protection measures when a structure with lightning risk is within a radius of 2km from the assessed structure even if this structure requires no lightning protection system.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.24 no.6
• /
• pp.67-74
• /
• 2010

Most of domestic low-voltage consumers are supplied from the TN-C system of KEPCO, but their load installations have established according to the national statutory standard for electrical installations based on the TT system. In this work, to propose the proper system earthing arrangements of ensuring the protection of information-technology equipment against lightning surges, the protection performance of TT and TN systems against lightning surges was investigated. As a result, when lightning surge was injected to the neutral line of distribution system, the potential difference between the equipment earth terminal and neutral point of low-voltage mains in a TT system was significantly raised. The TT system is not advised due to the risk of damage to the sensitive computer equipment. Main equipotential bonding is an important requirement for protection of low-voltage installations against lightning surges. The TN system provides the best means to reduce the incoming lightning surges through the neutral line of low-voltage service systems. In addition, It is highly recommended to install the additional earthing at the service position of low-voltage consumers.

• Proceedings of the KIEE Conference
• /
• 2003.07a
• /
• pp.558-560
• /
• 2003

The effects of surge arresters for protection of transmission systems against direct lightning strokes have already been investigated using the digital simulation program EMTP. Distribution lines are spanned on a much large area as compared to transmission lines, and therefore, are more often susceptible to lightning strokes. This paper analyzes the overvoltages on underground cable system against direct lightning strokes to the overhead ground wire using the digital simulation. The effects of lightning protection methods, such as lowering the grounding resistance and installing the surge arrester, for preventing overvoltages on underground cable system caused by direct lightning strokes to the overhead ground wire is investigated. Several schemes have been proposed to protect underground cables. This paper summarizes the main results of a study aimed at analysis of lightning overvoltages in variety underground feeders protected by metal-oxide arresters. This study will provide insulation coordination methods for reasonable system design in 22.9kV underground cable system.

• KIEE International Transactions on Electrophysics and Applications
• /
• v.3C no.4
• /
• pp.117-122
• /
• 2003

The AC power lines and signal lines of info-communication networks are routed on overhead poles and are highly exposed to lightning strikes. Due to the potential difference between grounding points of AC power lines and signal lines, the electronic equipments connected to the signal lines can easily be damaged by lightning surges. In this work, in order to develop reliable methods of protecting information and communication facilities from lightning surges, the reliability and performance of SPDs (surge protective devices) were experimentally investigated in an actual-sized test circuit. The behaviors of SPDs against lightning surges from AC power lines and signal lines and the coordinated effects of SPD installation methods were evaluated. As a consequence, it was confirmed that the bypass arrester methods and common grounding system are both highly effective.

• Journal of Advanced Navigation Technology
• /
• v.18 no.5
• /
• pp.445-454
• /
• 2014

In this paper, we introduce measures designed content for RTCA DO-160 F, Section 22 tests performed to verify the effects of indirect lightning and testing process of the test was carried out in the multi-purpose display certification process. This is referred to as indirect effects of lightning capability of an aircraft having electrical electronic equipment failure or damage to bring lightning induced voltages. In order to protect the avionics from lightning indirect effects of these aircraft are analyzing the effects of lightning strikes on aircraft and aircraft systems and interior design needs protection against the threat on their part. In this paper, we introduce RTCA DO-160 F, component selection process according to Section 22 category selection method and the selected level for determining the level of such measures for protection against lightning of multipurpose display for this aircraft. It also introduces the actual test process to confirm that the designed effectiveness of the selected part. We expect a good example of the lightning planned for future development of measures designed avionics through each step of the process introduced this.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 1995.04b
• /
• pp.358-362
• /
• 1995

Precision electronic equipments are composed of sophisticated microcircuits that are extremely vulnerable to lightning-caused voltage spike. This transient voltage spike may cause upset, latent failure or interference on electronic equipments. In order to develop efficient lightning protection measures on AC power lines for a road traffic controller, experimental surge immunity tests were conducted according to IEC standard 801-5. The combination of gas tube arrester and metal-oxide varistor was installed at the input of AC power lines and the silicon avalanche suppressor installed at the output of DC power supply as lightning protection measures.

• Proceedings of the KIEE Conference
• /
• 1994.07b
• /
• pp.1568-1570
• /
• 1994

Laser-triggered-lightning is protection methed for power apparatus against lightning. It is necessary to understand the generation mechanism of laser produced plasma. So production of long distance laser-plasma-channel was numerically analyzed with electron growth equation and laser transport equation.

• Journal of the Korean Society for Aviation and Aeronautics
• /
• v.25 no.4
• /
• pp.130-140
• /
• 2017

Lightning protective design of an aircraft fuel system is closely related to the safety of the flight. Recently, composite material in building an aircraft becomes more important because it can reduce the weight of the aircraft. The composite materials decrease the protection against the effect of lightning. Lightning protective design of metal material aircraft has been researched for a long time and the design technique has been announced widely. However, research on the lightning protective design using composite material aircraft is very limited. In this study, lightning protective design for fuel tank structural component, access cover, fuel filler cap and drain valve in carbon fiber composite material aircraft have been presented. To show the compliance with FAA airworthiness standard regarding the presented protection designs, three steps, including lightning strike analysis, lightning environment analysis and certification test, were conducted in accordance with FAA AC 20-53.

• The Transactions of the Korean Institute of Electrical Engineers A
• /
• v.53 no.8
• /
• pp.454-460
• /
• 2004

The effects of surge arresters for protection of transmission systems against direct lightning strokes have already been reviewed using Electromagnetic Transients Program(EMTP). Distribution lines are spanned in much larger area than transmission lines, and therefore, are more susceptible to lightning strokes. We have modelled the 22.9kV underground distribution cable systems that have arresters and grounding wires. And this paper analyzes the overvoltages on underground distribution cable systems when direct lightning strokes strike on the overhead grounding wire using EMTP. Then we investigated that (1) the effects of lightning stroke according to underground distribution cable length (2) voltages at the riser pole and at the cable terminal according to installation of arrester. This study will provide insulation coordination methods for reasonable systems design in 22.9kV underground distribution cable systems.