• Transactions on Electrical and Electronic Materials
• /
• v.10 no.1
• /
• pp.9-15
• /
• 2009

There is a growing demand for a high voltage silicone rubber composite with high mechanical property and high electrical property. The effect of modified cross-linking agent on the mechanical, electrical properties, and short-circuit test performance of silicone rubber insulators have been investigated. To use base polymer, the various silicone polymers were prepared by the equilibrium polymerization. Aluminum trihydrate surface was treated by vinyl silane. Liquid silicone rubber nanocomposite was prepared from the compounding of VPMPS, HPDMS, catalyst, and alumina trihydrate modified with 1,3,5-trivinyl-l,3,5-trimethylcyclotrisiloxane. The mechanical property and electrical property for insulation materials were measured, indicating the high tensile strength and the good short-circuit property.

• Proceedings of the KIEE Conference
• /
• 1997.07e
• /
• pp.1804-1806
• /
• 1997

Route conditions, applied voltage and the condition of stringing conductors should be considered in determining standard types and skeleton diagrams of towers. In skeleton diagrams the necessary number of insulators and the air clearance have been decided by the results of studies on insulation coordination. Galloping, sleet-jumping, sag characteristics and the possibility of closeness of conductors should be considered according to the condition of stringing conductor and the span. After reviewing those factors, it is necessary to determine the minimum vertical and horizontal distance for the safety of transmission lines under any circumstances. Also it should be economical.

• Proceedings of the KIEE Conference
• /
• 1997.07d
• /
• pp.1497-1499
• /
• 1997

This paper dealt with the surface aging characteristics of silicone rubber used as the surface material of outdoor polymer insulators under accelerated aging condition. There are many aging factors in natural environment. In this paper, the silicone rubber were accelerated to evaluate their performance against salt fog, that is, they were dipped in pure water and salt water under boiling condition. Then, contact angle and SEM(Scanning Electron Microscope) were used to estimate surface hydrophobicity, and dielectric loss($tan{\delta}$) and surface leakage current were measured to observe the electrical characteristics.

• Journal of Magnetics
• /
• v.10 no.2
• /
• pp.71-75
• /
• 2005

An effective method, i.e., the solid atom method, is suggested to obtain the Coulomb interaction parameter, U, and the Hund exchange coupling constant, J, for use in the LDA+U calculation. The par~meters are obtained self-consistently during the LDA+U calculation. The method is applied to typical transition metal oxides and $MnB^{VI}(B^{VI}=S,Se,Te)$. The U values for the transition metal oxides have similar magnitude to previous calculations although they are obtained by a much simpler method. $MnB^{VI}s$ have been characterized as crossroads materials between charge transfer and band insulators by the LDA+U calculation.

• Proceedings of the KSR Conference
• /
• 2009.05a
• /
• pp.1963-1969
• /
• 2009

This paper introduces method to estimate pollutant negative influence to polymer type insulator according to the international standard. To accomplish this goal, effective sample collecting method was surface was collected directly with the same dimension. Distilled Through this method pollute is easily and accurately collected. The second step is pollutant analysis. Several analyze item is selected such as quantity, conductivity, contact angle, Optical Microscope(OM), IR spectrometer(FT-IR), Equivalent Salt Deposit Density(ESDD), Thermal Analyzer(TA) and ICP-AES. The third step, best represent tunnel was selected considering location, length and natural surroundings. Also to consider the difference at inside the tunnel, several bracket insulators were selected along to the location. To make the result precise, above procedure was repeated several times at the same target. Finally relation among type of train, numbers of movement, surroundings, length will be considered in combination with the pollution. With this result pollute map for KORAIL could be accomplished and inspect period will be optimized case by case.

• Korean Journal of Materials Research
• /
• v.24 no.3
• /
• pp.135-139
• /
• 2014

To obtain the transistor with ambipolar transfer characteristics, IGZO/SiOC thin film transistor was prepared on SiOC with various polarities as a gate insulator. The interface between a channel and insulator showed the Ohmic and Schottky contacts in the bias field of -5V ~ +5V. These contact characteristics depended on the polarities of SiOC gate insulators. The transfer characteristics of TFTs were observed the Ohmic contact on SiOC with polarity, but Schottky contact on SiOC with low polarity. The IGZO/SiOC thin film transistor with a Schottky contact in a short range bias electric field exhibited ambipolar transfer characteristics, but that with Ohmic contact in a short range electric field showed unipolar characteristics by the trapping phenomenon due to the trapped ionized defect formation.

• Proceedings of the KIEE Conference
• /
• 1994.07b
• /
• pp.1351-1353
• /
• 1994

High strengh pocelain insulators with 35wt% alumina were manufactured by wet produce technique. The microstructure and crystalline phases of this samples and the effect of CaO addition to insulator bodies were studied. Electrical and mechanical properties (permittivity, dissipation factor, modulus of rupture, Young's modulus etc,) were studied. The relation between microstructure and electrical, mechanical properties were analyzed.

• Journal of the Korean Institute of Telematics and Electronics A
• /
• v.32A no.7
• /
• pp.58-68
• /
• 1995

Polysilicon capacitors with pyrogenic oxide and TEOX oxide as insulators were fabricated to develop capacitors which can be applied to analog CMOS IC, and the characteristics of the capacitors were compared with each other. The morphology of bottom polysilicon in pyrogenic oxide capacitor is degraded due to the generaged protuberances of the polysilicon grain during oxidataion. The polysilican capacitor with pyrogenic oxide of 57 nm thickness showed that the effective potential barrier height of 0.45 eV is much less than that of MOS capacitor (3.2 eV)when the top electrode is biased with a positive volgate. The morphology of the polysilicon capacitor with TEOS oxide, however, was not degraded during oxide deposition by LPCVD. The polysilicon capacitor with TEOS oxide of 54 nm thickness showed the effective potential barrier height of 1.28 eV when the top electrode is biased with a negative voltage. Therefore, it is concluded that the polysilicon capacitor with TEOS oxide is more applicable to analog CMOS IC than the pyrogenic oxide polysilicon capacitor.

• Proceedings of the IEEK Conference
• /
• 2000.07a
• /
• pp.233-236
• /
• 2000

A portable equipment that measures a current and voltage waveform of power transmission lines is pro-posed. In the equipment, the current and voltage, respectively, are detected by a loop coil and a capacitor clamped around the power lines. The detected data is transmitted by an FM wave to the receiver on the ground station. Since the receiver is isolated from the power lines, we do not require high potential insulators for the measurement of current and voltage. The proposed equipment is therefore, small-sized, light, and low in the cost of production. Experimental results presented here show that the equipment can monitor the current flowing in single wire over a ground plane and the potential of the wire.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.28 no.4
• /
• pp.16-20
• /
• 2014

To prevent any accident in electric power utilities, many researches for inspection and diagnosis deteriorations occurring by corona discharges have been continuously studying. Inspection and diagnosis of electric power utility is very important to prevent an accident. This paper studies a measurement of ultra-violet(UV) ray of corona discharges on polymer insulators using an UV sensor array with an optic lens. The detection of an UV signal begins at 60kV, which is about 37.5% of the breakdown voltage of the polymer insulator and the stronger the high voltage increased to the polymer insulator was. It can be determined that the polymer insulator mounted on a live part must be examined when the discharge risk exceeds approximately 40%. In conclusion, the status of power utilities can be checked using an UV sensor.