• Title/Summary/Keyword: AC breakdown test

Search Result 98, Processing Time 0.028 seconds

Insulation Characteristics of the Model Cable for 22.9 kV Class HTS Power Cable

  • Kim, Hae-Jong;Seong, Ki-Chul;Cho, Jeon-Wook;Kwag, Dong-Soon;Cheon, Hyeon-Gweon;Kim, Sang-Hyun
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
    • /
    • 2005.07a
    • /
    • pp.542-543
    • /
    • 2005
  • In this paper, describes the fabrication and dielectric insulation characteristics experimental results of the model cable for the 22.9kV class HTS power cable. The model cable were tested with partial discharge(PD), AC and impulse withstand voltage in liquid nitrogen($LN_2$) and liquid nitrogen pressure. In these test results, PD inception stress and AC, impulse breakdown strength increase as the pressure of the liquid nitrogen increases.

  • PDF

A Study on the Insulation Characteristics for Stator Windings of IGBT PWM Inverter-Fed Induction Motors

  • Hwang, Don-Ha;Kang, Dong-Sik;Kim, Yong-Joo;Lim, Tae-Hoon;Bae Sung-Woo;Kim Dong-Hee;Ro Chae-Gyun
    • Journal of Power Electronics
    • /
    • v.3 no.3
    • /
    • pp.159-166
    • /
    • 2003
  • The winding insulation of low-voltage induction motors in adjustable-speed drive system with voltage-fed Inverters is substantially stressed due to the uneven voltage distribution and excessive voltage stress (dv/dt), which result in the premature insulation breakdown In this paper, the detailed insulation test results of 26 low-voltage induction motors are presented. Six different types of insulation techniques are applied to 26 motors. The insulation characteristics are analyzed with partial discharge, discharge inception voltage, AC current, and dissipation factor tests Also, insulation breakdown tests by high voltage pulses are performed, and the corresponding breakdown voltages obtained.

A Study on the Electrical Breakdown Characteristics of Air according to Electrode Gap (전극 간격에 따른 공기의 절연파괴 특성에 관한 연구)

  • Kang, Jong O;Lee, Onyou;Kim, Junil;Bang, Seungmin;Lee, Hongseok;Lee, Jong Doug;Kang, Hyoungku
    • The Transactions of the Korean Institute of Electrical Engineers P
    • /
    • v.63 no.4
    • /
    • pp.301-306
    • /
    • 2014
  • Recently in accordance with the rapid development of the industrial society, the accidents caused by dielectric breakdown have been increasing in power grid. It is important to prevent the dielectric breakdown of a high voltage apparatus to reduce the damage from electrical hazards. To establish an electrically reliable database of insulation design criteria for high voltage apparatus, a study on dielectric characteristics test is indispensable. In this study, dielectric characteristics according to field utilization factors (${\xi}$) which are represented as the ratio of mean electric field to maximum electric field are investigated. the dielectric breakdown experiments by using several kinds of electrode systems made with stainless steel are performed by AC breakdown voltage under air-insulation. Also, the experimental results are analyzed by the Weibull distribution. As a result, it is found that the dielectric characteristics of air-insulation are determined by ${\xi}$ as well as arrangement of electrode systems. It is considered that the results of this study would be applicable to designing the air-insulated high voltage apparatuses.

A Study on Insulating Design and Test of Mini-Model windings for a 22.9 kV Class HTS Transformer Reducing AC Loss (저손실 22.9 kV급 고온초전도 변압기를 위한 미니 모델 권선의 절연 설계 및 시험 연구)

  • Baek, Seung-Myeong;Cheon, Hyeon-Gweon;Nguyen, Van Dung;Kwag, Dong-Sun;Lee, Chang-Hwa;Kim, Hea-Jong;Kim, Sang-Hyun
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
    • /
    • 2004.05b
    • /
    • pp.94-99
    • /
    • 2004
  • This paper presents experimental data from model windings with different arrangement of coil in order to provide information to design a 22.9 kV class HTS transformer. Before experiment, the composite insulation of two different type of HTS transformers are investigated. The first basic of investigation is a breakdown characteristic of liquid nitrogen and flashover characteristic on the GFRP surface under ac and impulse, The second investigation is insulation design, manufacture and test of model windings. These include a AC withstand voltage test of 50 kV rms and a lighting impulse test of 150 kV at peak.

  • PDF

Insulation rehabilitation of water tree aged cables by silicone treatment (실리콘 처리에 의한 수트리 열화케이블의 절연회복)

  • 김주용;송일근;한재홍;이동영;문재덕
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
    • /
    • v.14 no.1
    • /
    • pp.14-21
    • /
    • 2000
  • This paper presents the results of performance evaluation of silicone treatment technique which was developed for the insulation rehabilitation of water tree aged XLPE power cables. We treated the water tree aged 325 [$\textrm{mm}^2$] CN/CV cables with silicone, and then analyzed the degree of insulation rehabilitation as a function of time. AC breakdown test was conducted to evaluate insulation rehabilitation. The diagnosis test using relaxation current measurement and the characteristic analysis of insulation were also performed to estimate silicone treated cable. AC breakdown strength of silicone treated cable for one year was increased, resulting from the chemical reaction between silicone fluid and water. This experiment showed that the silicone treatment technique was effective for insulation rehabilitation of the water tree aged cables.

  • PDF

An Amendment of the VLF tanδ Criteria to Improve the Diagnostic Accuracy of the XLPE-insulated Power Cables (XLPE 절연케이블의 열화진단 정확도 향상을 위한 VLF tanδ 판정기준 개선)

  • Lee, Jae-Bong;Jung, Yeon-Ha
    • The Transactions of The Korean Institute of Electrical Engineers
    • /
    • v.59 no.9
    • /
    • pp.1644-1651
    • /
    • 2010
  • VLF $tan{\delta}$ diagnosis technology is introduced in IEEE Std 400 and proposed as evaluation criterion in an effective way of detecting water tree which mainly causes the failure of XLPE insulated cables. In order to inspect the accuracy of the VLF $tan{\delta}$ method for XLPE insulated power cables in Korean distribution system, diagnosis for 41 cables which were being serviced in the fields has been carried out and they were removed for AC breakdown voltage test after. Regarding the 41 cables, it was hard to confirm any relation between the VLF $tan{\delta}$ values and AC breakdown voltages and also water tree in the insulation was not detected. However, the other cables were failed several days after the diagnosis of the 41 cables. Water trees were found and their VLF $tan{\delta}$ values were also much higher than the criterion of IEEE standard. It has been ascertained that we need to change the IEEE criteria in order to improve the accuracy of detecting water trees by additional analyzing of field examples of failure and case studies from overseas countries and therefore amended VLF $tan{\delta}$ test voltage and evaluation criteria have been proposed.

Insulation Design for a 13.2kV/630A High-Tc Superconducting Fault Current Limiter (13.2kV/630A급 고온초전도 한류기의 절연설계)

  • Kang, Hyoung-Ku;Lee, Chan-Joo;Ko, Tae-Kuk;Seok, Bok-Yeol
    • Proceedings of the KIEE Conference
    • /
    • 2007.07a
    • /
    • pp.941-942
    • /
    • 2007
  • The superconducting fault current limiter (SFCL) consists of superconducting coil for limiting the fault current and cryogenic cooling system for keeping the coil in superconducting condition. The study on the insulation design for superconducting coil and cryogenic cooling system should be elaborately performed to develop a high voltage SFCL. In this paper, insulation design of solenoid coil for 13.2kV/630A SFCL is performed through the AC dielectric breakdown test and lightning impulse dielectric strength test. The dependence of dielectric characteristics on the magnitude of liquid nitrogen pressure is also investigated. Through the investigation, it is verified that dielectric characteristics of sub-cooled nitrogen are strongly enhanced by the pressurization. The electrical insulation design of 13.2kV/630A SFCL is performed by applying the experimental results. The successful insulation design for development of 13.2kV/630A SFCL is confirmed by AC dielectric breakdown tests.

  • PDF

Characterization of Water Vapor Transmission & Dielectric Breakdown in Insulation Materials for Jacket Compound (자켓 컴파운드용 절연재의 수증기투과 및 절연파괴 특성)

  • Song, Jae-Joo;Han, Jae-Hong;Song, IL-Keun;Han, Yong-Hee;Han, Byung-Sung
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
    • /
    • 2001.11b
    • /
    • pp.52-56
    • /
    • 2001
  • Experiments of 2 type on insulating compounds accomplished to change PVC using in URD(Underground) power cable jacketing. one was DB (Dielectric Breakdown) test on the pure base resins and the others were WVT(Water Vapor Transmission) test on the compounds which contained C/B(Carbon Black), anti-oxidant to base resin. a kind of specimens made by pressing to resin of pellet or lump form was HDPE(High Density Polyethylene), MDPE(Medium Density Polyehylene), LDPE(Low Density Polyethylene), LLDPE(Linear Low Density Polyethylene), PVC (Polyvinyl Chloride). As a results of AC DB and WVT test, we saw that strength of Insulation was HDPE > LLDPE ≒ MDPE > LDPE and WVT ratio was HDPE < LLDPE < MDPE < LLDPE ≒ LDPE${\ll}$PVC. WVT of PVC using for jacket showed characteristic 15 times more than MDPE or LLDPE. Therefore, to development of watertightness cable, our works present need of Changing in insulating materials

  • PDF

Breakdown Characteristics and Lifetime Estimation of Rubber Insulating Gloves Using Statistical Models

  • Kim, Doo Hyun;Kang, Dong Kyu
    • International Journal of Safety
    • /
    • v.1 no.1
    • /
    • pp.36-42
    • /
    • 2002
  • This paper is aimed at predicting the life of rubber insulating gloves under normal operating stresses from relatively rapid test performed at higher stresses. Specimens of rubber insulating gloves are subject to multiple stress conditions, i.e. combined electrical and thermal stresses. Two modes of electrical stress, step voltage stress and constant voltage stress are used in specimen aging. There are two types of test for electrical stress in this experiment: the one is Breakdown Voltage (BDV) test under step voltage stress and thermal stress and the other is lifetime test under constant voltage stress and temperature stress. The ac breakdown voltage defined as the break-down point of insulation that leakage current excesses a limit value, l0mA in this experiment, is determined. Because the very high variability of aging data requires the application of statistical model, Weibull distribution is used to represent the failure times as the straight line on Weibull probability paper. Weibull parameters are deter-mined by three statistical methods i.e. maximum likelihood method, graphical method and least squares method, which employ SAS package, Weibull probability paper and FORTRAN, respectively. Two chosen models for predicting the life under simultaneous electrical and thermal stresses are inverse power model and exponential model. And the constants of life equation for multistress aging are calculated using numerical method, such as Gauss Jordan method etc.. The completion of life equation enables to estimate the life at normal stress based on the data collected from accelerated aging test. Also the comparison of the calculated lifetimes between the inverse power model and the exponential model is carried out. And the lifetimes calculated by three statistical methods with lower voltage than test voltage are compared. The results obtained from the suggested experimental method are presented and discussed.

Partial Discharge Phenomenon with $SF_6$ Gas Pressures in Insulation consisting of Insulation Paper and $SF_6$ Gas (SF_6 가스와 절연지의 절연계에서 가스압력에 따른 부분방전현상)

  • 선종호;김광화;박정후;조정수
    • The Transactions of the Korean Institute of Electrical Engineers C
    • /
    • v.50 no.2
    • /
    • pp.65-71
    • /
    • 2001
  • This paper describes partial discharge phenomenon with SF6gas pressures in insulation consisting of insulation paper and SF6 gas. We made the specimens with SF6 gas gaps which exist between aramid papers and electrodes and calculated the electric field intensity in the these gaps. We measured the partial discharge inception voltages and the AC breakdown voltages with the test method of IEC 60060-2 and did the partial discharge degradation experiments with a constant voltage. According to gas pressures, the breakdown voltages in SF6gas gaps were calculated by Paschen's law. And these results showed the ability applying partial discharge inception voltages evaluation to Paschen's law and the relationship between the PD quantities occurring insulation breakdown and PD occurring area.

  • PDF