• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.17 no.3
• /
• pp.333-339
• /
• 2004

For an electrical insulation design of HTS cable, it is important to understand the dielectric characteristics of insulation materials in L$N_2$ and the insulation type. Generally, the electrical insulation of HTS Cable is classified into two types of the composite insulation and solid insulation type. In this research, we selected the insulation paper/L$N_2$ composite insulation type for the electric insulation of a HTS cable, and studied electric insulation characteristics of synthetic Laminated Polypropylene Paper(LPP) in liquid nitrogen(L$N_2$) for the application to high temperature superconducting(HTS) cable. Furthermore, we compared the breakdown characteristics of the butt gap and bended mini-model cable. It is necessary to understand the winding parameter of insulation paper/LN2 composite insulation.

• Progress in Superconductivity and Cryogenics
• /
• v.5 no.3
• /
• pp.43-47
• /
• 2003

For an electrical insulation design of HTS cable, it is important to understand the dielectric characteristics of insulation materials in $LN_2$ and the insulation type. Generally, the electrical insulation of HTS Cable is classified into two types of the composite insulation and solid insulation type. In this research, we selected the insulation paper/$LN_2$ composite insulation type for the electric insulation of a HTS cable, and studied electric insulation characteristics of synthetic Laminated Polypropylene Paper (LPP) in liquid nitrogen ($LN_2$) for the application to high temperature superconducting (HTS) cable. Furthermore, we compared the breakdown characteristics of the butt gap and bended mini-model cable. It is necessary to understand the winding parameter of insulation paper/$LN_2$ composite insulation.

• The Transactions of the Korean Institute of Electrical Engineers B
• /
• v.53 no.5
• /
• pp.338-343
• /
• 2004

In general, the insulation and protective sheaths on electrical conductors are made of combustible substances like PVC, natural or synthetic rubbers, and other organic or synthetic materials. When an electrical fire starts due to overheating of conductors/joints or sparking/arcing, the first thing to ignite is usually the insulation on the cables. When the insulation bums, the produced fumes are very toxic. To solve the problem, we have surely need the fire resistance cable that doesn't bum in a high temperature and emit toxic fume for operating a disaster prevention installation. In this paper, we have simulated the thermal analysis for the fire resistance cable according to the values of current in a overload and a short, and the values of outside flame with the fire resistance cable of the L's company product(600 V, FR-8 : Four Core) using the finite element method(Flux2D).

• Korean Journal of Materials Research
• /
• v.12 no.2
• /
• pp.103-111
• /
• 2002

The thermally insulated underground pipelines have been used for district heating system. The sensor wire embedded in the insulation was used for monitoring the insulating resistance between the sensor wire and the pipe. The resistance measurement system detects corrosion of steel pipe under insulation. The corrosion and stress corrosion cracking(SCC) characteristics of sensor wire in synthetic ground water were investigated using the electrochemical methods and constant load SCC tests. The polarization tests were used to study the electrochemical behavior of sensor wire. The sensor wire was passivated at temperatures ranging from 25 to $95^{\circ}C$. However, the applied sensing current larger than passive current resulted in breakdown of passive film. The constant load SCC tests were performed to investigate the effects of applied current and load on the fracture behavior. Stress-corrosion cracks initiated at pits that were produced by sensing current. The growth of the pit involves a tunnelling mechanism, which leads to ductile fracture.

• Fire Science and Engineering
• /
• v.32 no.2
• /
• pp.30-37
• /
• 2018

This study is an analysis of combustion characteristics of synthetic insulation materials such as houses and warehouses. Using combustion cone calorimeter and SEM, the researching has experimented combustion characteristics of four kinds of materials such as flame retardant styrofoam, general styrofoam, urethane and gypsum board. And analyzed. As a result of the test, the ignition time (TTI) for the thermal insulation material was found at 27 s~43 s, and the flame retardant styrofoam was ignited at the lowest TTI at 27 s and disappears at 28 s. In addition, the maximum heat release rate (peak HRR) and average heat release rate (mean HRR) of each material were expressed in the following order: urethane> flame retardant styrofoam> styrofoam> gypsum board. Also, the total smoke release ($m^2/m^2$) was the largest at $30.798m^2/m^2$ in flame-retardant styrofoam. The general CO concentration of styrofoam was 0.275 kg/kg and the emission concentration was 12.807 kg/kg. The residues showed the highest 0.029 g in the gypsum board among the above materials.

• Journal of the Korea Institute of Building Construction
• /
• v.18 no.6
• /
• pp.559-567
• /
• 2018

In the case of fire, surface treatment agents used in external insulation finishing methods are substances that are vulnerable to fire due to thin finishes and the combustion of polymers. In this study, it was expected that the performance of surface preparation mortars could be improved by using expandable graphite with excellent thermal performance. Experimental results showed that the mechanical properties of surface preparation mortar were improved by using the fly ash and silica fume. Surface treatment materials using expanded graphite have a characteristic of expanding when a fire occurs. It has been shown that heat-swellable surface treatment materials can reduce the penetration of heat sources into the surface of synthetic insulation.

• Journal of the Korean Recycled Construction Resources Institute
• /
• v.7 no.4
• /
• pp.395-404
• /
• 2019

In the case of fire, surface treatment agents used in external insulation finishing methods are substances that are vulnerable to fire due to thin finishes and the combustion of polymers. In this study, it was expected that the performance of surface preparation mortars could be improved by using expandable graphite with excellent thermal performance. Experimental results showed that the mechanical properties of surf ace preparation mortar were improved by using the fly ash and silica fume. Surface treatment materials using expanded graphite have a characteristic of expanding when a fire occurs. It has been shown that heat-swellable surface treatment materials can reduce the penetration of heat sources into the surface of synthetic insulation.

• Transactions on Electrical and Electronic Materials
• /
• v.8 no.3
• /
• pp.143-146
• /
• 2007

Polymer insulators are used widely in variable fields for high voltage insulation and separating people from high voltage charging parts for safety and also supporting overhead power line in electric railway. But it may be broken down by tracking path resulting from continuous surface discharge. This paper has investigated synthetically both the characteristics of electrical aging using precision CT(current transformer) and the thermal aging using thermography method. Electrical aging was analyzed for time-frequency region and thermal aging was illustrated by image processing method. This synthetic method may be an appropriate one to evaluate the surface degradation of polymer insulator.

• Elastomers and Composites
• /
• v.46 no.1
• /
• pp.29-36
• /
• 2011

The term 'thermal insulating materials' describes a class of materials which can improve the thermal efficiency by reducing the thermal conduction, convention and radiation between the inside and outside of the system. As a thermal insulating material, numerous industrial applications are possible including the automobile, aerospace, aviation, and petrochemical. Especially, the silica aerogel, with their superior thermal insulating behavior, has been widely used as thermal insulating materials. Because the mechanical properties of the silica aerogel cannot meet the industrial demand, use of the silica aerogel is limited. This article aims to review the thermal insulating materials and silica aerogel, and to introduce the silica aerogel/polymer composites.

• Journal of the Korean institute of surface engineering
• /
• v.54 no.3
• /
• pp.152-157
• /
• 2021

The pseudocapacitor has a high energy density characteristic because it accumulates charges through a paradic redox reaction. However, due to its strong insulation properties, metal hydroxides should be designed as structural systems optimized for charge transfer to support fast electron transport. Also, Nickel material is weak to heat and is easily deformed when used as a cathode material, so stability must be secured. In this study, nickel hydroxide was produced by electrodeposition to secure the stability of nickel. Electrodeposition is a synthetic method suitable for growing optimized nickel hydroxide because it allows fine control. Nickel hydroxide (Ni(OH)₂) is a metal hydroxide used as a pseudocapacitor anode due to its high capacitance, electrical conductivity and resistance. Therefore, in order to determine how Ni(OH)₂ nanosheets are formed and what are the optimization conditions, various measurement methods were used to focus on structural growth of nanosheets produced by electrodeposition.