• Title/Summary/Keyword: polarity measurement

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Determination of Charged Particles and their Polarity by Temperature Gradient Thermally Stimulated Measurement (온도구배 열자격 측정에 의한 하전입자의 구별 및 극성 판정)

  • 권영수;강도열;국상훈
    • The Transactions of the Korean Institute of Electrical Engineers
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    • v.38 no.8
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    • pp.600-609
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    • 1989
  • A thermally stimulated measurement using a temperature gradient has been applied to the study of charged particles and their polarity n polymers. From the experimental results on a cross-linked polyethylene (XLPE) film is found that the TSC peaks of the trapped carriers in C peak are due to the negative polarity which is electron and the ionic carriers having negative polarity show D peak.

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Determination of Polarity in Trap Carriar by Temperature Gradient Thermally Stimulated Measurement (온도구배 열자격 측정에 의한 Trap Carriar의 국성판정)

  • 권영수;강도영;국상훈
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 1989.06a
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    • pp.29-34
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    • 1989
  • A Thermally stimulated measurement using a temperature gradient has been applied to the study of charged particles and their polarity in polymer. Our experimental results on a cross-linked polysthylen(XLPE) film can be obtained, observing the TSC peaks of the trapped carriers in C peak determinated negative polarity that is electron.

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A Study on the Space Charge Polarity Measurement Teasurement Technology of Cross-Linked Polyethylene for Power Cable (전력케이블용 가교폴리에틸렌의 공간전하 극성측정기술에 관한 연구)

  • 국상훈;서장수;김병인;박중순
    • The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.6 no.6
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    • pp.23-31
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    • 1992
  • Charged particle in the polymers is supposed to affect the electrical conduction and to lead them th dielectrical breakdown finally. So we measured the space charge distribution made by application of high electric field and evaluated the polarity of the charged particle affected on electrical conduction and space charge formed in the insulating materials by using temperature gradient thermally stimulated current measurement method(TG-TSC measurement). As a result, in the cross-linked polyethylene, A-peak was caused from dipole polarization, C-peak was caused from ionic space charge polarization and D-peak was injected trap hole. Also we found it crossible the evaluated the polarity of injected trap carrier and electron(or hole) of carrier trap in the cross-lined polyethylene. We found that ${\gamma}$-ray irradiated low density polyethylene had a relation to the electronic trap and we also could get the value of electric field distribution in the samples of which evaluation was available.

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Pulse Waveform Simulation of Partial Discharges for HV XLPE Cable Joints (초고압 XLPE 케이블 접속함의 부분방전 펄스파형 시뮬레이션)

  • Kim, Jeong-Tae
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.67 no.1
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    • pp.75-81
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    • 2018
  • In this study, the simulation of partial discharge pulse waveform have been performed for the typical joints such as EBA and PMJ in the HV underground transmission XLPE cable system in order to improve the understanding of partial discharge pulse waveform and the on-site measurement accuracy of partial discharges. FDTD simulation technique was adopted for the simulation and has been shown to be suitable for partial discharge simulation of power cables in terms of pulse propagation characteristics and waveform formation. The simulation results for the EBA showed that the second not-so-large opposite polarity peak appeared after the first negative polarity peak and the measurement sensitivity was the highest near the bottom of the EBA copper box. In the analysis results for PMJ, the magnitude of the second opposite polarity peak was large enough to compare with the first peak, and the measurement sensitivity at the end of the PMJ copper box was the highest. These simulation results show considerable similarity with the on-site measurement, and it would be very useful for the partial discharge measurement of HV XLPE cable systems.

A Study on the Space Charge Measurement Technique and Carrier Polarity of Insulating Materials on Power Cable (전력케이블용 절연재료의 캐리어 극성 및 공간전하 측정기술에 관한 연구-PE-EVA에서의 하전입자의 거동)

  • 국상훈;박중순;강용철;권영수
    • The Transactions of the Korean Institute of Electrical Engineers
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    • v.41 no.2
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    • pp.185-191
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    • 1992
  • In this paper, it is attempted to distinguish the charged particles and to judge the polarity by the use of Thermally Stimulated Current(TSC) and Temperature Gradient Thermally Stimulated Surface Potential Measurement(TG-TSSP)with experimental insulation material XLPE-EVA for power cables which is made by blending cross-linked polyethylene(XLPE) and ethylene-vinylacetate copolymer(EVA). In addition, it is performed to investigate the effect of EVA blending. From the experimental results, it is known that for the case of XLPE-EVA blended experimental material, the generation of space charged electric field is not obtained in the high temperature region due to the obatruction of the injection of trapping carrier by the electron and the positive hole.

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Study on IPT Characteristics of LSR / Nano Silica Composites for HVDC (HVDC용 LSR/Nano Silica Composites의 IPT특성 연구)

  • Park, Jae-Jun
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.68 no.1
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    • pp.61-68
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    • 2019
  • Only the power is converted from AC to DC, in accordance with IEC 60587 based test method, in order to develop the LSR(Liquid Silicone Rubber) insulator material for HVDC, the experiment of Inclined Plate Tracking and Erosion Resistance was conducted. A contaminant (2.5 mS/cm: ammonium chloride) was applied at a rate of 0.3 ml/min and a voltage of ${\pm}3.5kV$, and was evaluated on the basis of 60 mA/2s. The samples were prepared by dispersing LSR/Nano silica_25wt% Composites in LSR. The erosion phenomena of surface discharge and tracking due to DC polarity and negative polarity were measured by image, leakage current maximum and thermal camera. The thermal imaging camera measured the surface temperature generated by the joule heat of the leakage current due to the drying discharge and the conductive current. After the measurement, the tracking and erosion mechanisms were evaluated for erosion weight, erosion depth and erosion length. Positive and negative polarity of LSR/Nano Silica_25wt% composite Tracking and erosion results show that positive polarity is more severe than negative polarity.

Characteristics of Dielectries in $SF_6$ Accoding to a change in Temperature (온도변화에 따른 $SF_6$ 가스의 절연특성)

  • Lee, Bok-Hee;Kim, Hoe-Gu;Park, Geon-Hun;Lee, Kyu-Sun;Kim, Dong-Sung
    • Proceedings of the KIEE Conference
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    • 2007.07a
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    • pp.1436-1437
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    • 2007
  • This paper presents the experimental results of the dielectric characteristics with temperature changes under highly non-uniform electric field in $SF_6$ gas. The impulse preliminary breakdown developments were investigated by the measurement of predischarge current and breakdown voltage. As a result, the first stremer corona is initiated at the tip of needle electrode, and bridges the test gap. Also the first stremer corona onset and breakdown voltages the negative polarity was much higher than that in the positive polarity in same temperature. In addition, the varition of temperature have a little effect on the positive polarity. On the other hand, in some cases negative polarity corona onset and breakdown voltages increased with increasing a high temperature.

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Characteristics of DC Corona Discharges Caused at the tip of a Needle-shaped Electrode Placed in the Homogeneous Electric Fields (균등전계 중에 놓인 침상 전극의 끝단에서 발생한 직류 코로나방전 특성)

  • Kim, Tae-Ki;Kim, Seung-Min;Lee, Bok-Hee
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.29 no.11
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    • pp.74-81
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    • 2015
  • In the measurement of atmospheric static electric field, it is important to know characteristics of corona discharges caused at the tip of test electrode. This paper presents the fundamental data of DC corona discharges that occurred at the tip of a needle-shaped electrode placed in the homogeneous background electric field which simulates the atmospheric static field under thundercloud. The major characteristics of interest for this purpose are the polarity effect of corona discharges and the magnitudes and time intervals of corona current pulses. The experimental set-up consists of the plate-to-plate configuration with a needle-shaped protrusion, DC power supply, and voltage and current measuring devices. As a result of experiments, the polarity dependence of corona pulses is significantly pronounced. The time intervals between successive corona pulses in the negative polarity is much longer than those in the positive polarity. The time intervals for both polarities is drastically decreased as the applied electric field is increased. Also the magnitudes of the positive corona pulses are slightly changed with an increase in applied electric field, but those of the negative corona pulses are linearly increased with increasing the applied electric fields.

A Few Applications of Polarity Correlation Method in a Frame of Deterministic Signals

  • Kim, io-Sasaki;Mariko Ikeda
    • 제어로봇시스템학회:학술대회논문집
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    • 2002.10a
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    • pp.86.1-86
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    • 2002
  • Polarity correlation is a simplified version of the usual, having a possibility of real-time processing without any reduction of precision. In this paper, its applicability in deterministic signals is first explored generally, by theoretical or numerical analysis of four kinds of the typical signals. Then, based on the results, its two applications are proposed, that are detection and demodulation of FSK signals in digital communication, and time delay estimasion in ultrasonic A-mode measurement. The effectiveness of the proposed applications is confirmed by its superior implementation ability and the results of numerical experiments under practical circumstances.

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Polarity Probing Two-Photon Fluorophores Based on [2.2]Paracyclophane

  • Woo, Han-Young;Korystov, Dmitry;Jin, Young-Eup;Suh, Hong-Suk
    • Bulletin of the Korean Chemical Society
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    • v.28 no.12
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    • pp.2253-2260
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    • 2007
  • A series of tetra donor substituted [2.2]paracyclophane-based two-photon absorption (TPA) fluorophores were synthesized in neutral and cationic forms. The imaging activity of overall set of fluorophores was studied by the two-photon induced fluorescence (TPIF) method in a range of solvents. We also measured a clear progression toward a longer photoluminescence lifetime with increasing solvent polarity (intrinsic photoluminescence lifetime, τi: ~2 ns in toluene → 12-16 ns in water). The paracyclophane fluorophores with this unique property can be utilized as an optical polarity probe for the biomolecular substrates. The combined measurement of the two-photon fluorescence microscopy (TPM) cell image and TPIF lifetime can give us a better understanding of the biological processes and local environments in the cells.