• 한국안전학회지
• /
• 제37권6호
• /
• pp.1-8
• /
• 2022

This study analyzed the characteristics of insulation resistance and operating time based on an accelerated degradation test of a low-voltage circuit breaker. The experimental sample used a molded case circuit breaker (MCCB) and an earth leakage circuit breaker (ELCB). After measuring the insulation resistance of the circuit breakers, the leakage current was affected by an external rather than an internal structure. Furthermore, the insulation resistance of the circuit breakers with accelerated degradation was measured using a Megger insulation tester. In the accelerated degradation test, aging times of five, ten, 15, and 20 years were applied according to a temperature derived using the Arrhenius equation. Circuit breakers with an equivalent life of ten, 15, and 20 years had increased insulation resistance compared to those with less degradation time. In particular, the circuit breaker with an equivalent life of ten years had the highest insulation resistance. Component analysis of the circuit breaker manufactured through an accelerated degradation test confirmed that the timing of the increase in insulation resistance and the time of additive loss were the same. Finally, after analyzing the operating time of the circuit breakers with degradation, it was confirmed that the MCCB did not change, but the ELCB breaker failed.

• 한국인터넷방송통신학회논문지
• /
• 제16권4호
• /
• pp.159-164
• /
• 2016

급증하고 있는 수요에 따른 고전력을 생산하기 위하여 발전소에서는 이에 대응하는 시설장비를 운영해야 한다. 규모는 점차 커지고, 기능이 다양해지고 있다. 발전소에서 불의가 사고가 발생하면 장비가 지장을 받게 되고, 막대한 경제적 손실 및 장애를 초래하게 된다. 사고 발생의 원인 중의 하나로서 케이블의 두 도체를 전기적으로 분리시키는 유전체의 기능이 약화되는 것이다. 케이블에 의한 사고를 미연에 방지하기 위하여 동작 상태를 감시 확인하여야 한다. 우리는 절연저항을 측정하기 위한 장비를 개발하여 서부발전(주)의 현장에 설치하여 운용 중이다. 변압기의 2차 측 와이(Y) 결선으로 연결된 모선은 생산된 전기를 외부 장치에 전송한다. 우리가 개발한 장비는 모선과 on/off 되는 케이블의 절연 저항을 측정하는 장비이다. 우리는 이 논문에서 하드웨어 구성을 위주로 우리가 개발한 장비를 소개한다.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2010년도 하계학술대회 논문집
• /
• pp.86-86
• /
• 2010

Recently, CV, CNCV, CNCV-W cable are used to transmit and distribute electric power. And a lot of researchers put more effort to realize high performance. The dielectric breakdown strength characteristic is a standard to design insulators. Examination of that is a main factor to determine long term insulation performance, which is used to diagnose Insulation deterioration. In this paper, we prepared XLPE, XLPE/nano-filler, LDPE/nano-filler for comparing each of the dielectric breakdown strength characteristics.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1997년도 하계학술대회 논문집 E
• /
• pp.1692-1695
• /
• 1997

This paper describes the relationship between the various non-destructive parameters and the breakdown voltage for the 17 kV, 300 MVA and the 22 kV, 500 MVA generators stator bars with polyester and epoxy/mica insulation respectively. Also, this study reports the results of an investigation into the factors which can assess the insulation condition of generator stator winding. Furthermore, a new parameter, Partial Discharge Index(PDI), is introduced as the valuable parameter for the assessment of insulation condition. The ratio between partial discharge increment and the stepwise voltage increment from the Discharge Inception Voltage (DIV) at the characteristic or resonant frequency band shows the close relationship between the breakdown voltage and PDI.

• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2009년도 춘계학술대회 논문집
• /
• pp.912-918
• /
• 2009

In this paper, we carried out a comparative analysis of partial discharge(PD) patterns caused by deterioration of cast-resin and oil insulation systems. Various electrode systems were fabricated such as needle-needle, needle-plane and plane-plane to simulate defects that may exist in the insulation system of transformers. A low-noise amplifier which has a gain of 40 dB and a frequency bandwidth of 500 kHz $\sim$ 30 MHz (-3 dB) was designed to detect small PD signals. From the analysis of acquired PD signals, we could find that a unique PD pattern is formed according to types of defect. These data will be applied usefully to diagnose insulation condition of transformers.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2005년도 제36회 하계학술대회 논문집 C
• /
• pp.2118-2122
• /
• 2005

This test was performed to assess the corelation of insulation deterioration condition with breakdown voltage of the stator winding of 3.3kV class induction motors which have been in service for 10 years after being installed in 1993. The insulation diagnostic tests include resistance, polarization index(P.I), dissipation factor$({\Delta}tan{\delta})$, maximum partial discharges (Qmax) and AC breakdown test. we evaluated the corelation of insulation diagnostic test with AC breakdown test for stator wilding of high voltage induction motor.

• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2008년도 추계학술대회 논문집
• /
• pp.1213-1219
• /
• 2008

The deterioration analysis of electric systems in diesel electric locomotives, which were used for over 30 years, was performed to understand current wear and safety information. The electric systems include electric generation, traction motors, control units, high-voltage cables, and wires. In this investigation, various types of performance testing, such as insulation resistance measurement and degradation tests, were conducted to assess the degree of current deterioration. Moreover, an infrared camera was employed to verify abnormal heating in cables and wires. In this paper, the new techniques for evaluation of deterioration in electric systems have been introduced.

• 조명전기설비학회논문지
• /
• 제25권11호
• /
• pp.73-82
• /
• 2011

The solid insulation system of stator windings in high voltage rotational machines is usually aging in accordance with long time operation. The partial discharge test have been known to check whether insulation deterioration exist or not, and the PD test can effectively diagnose a solid insulation condition regardless of during operation(on-line) or not(off-line). The on-line PD measurement have proven to be a successful technique in monitoring stator insulation condition nowadays. This paper describes the characteristics of comparing the on-line PD measurement data using PDMS-HG(Partial Discharge Monitoring System for Hydro-electric Generator) installed in field with the off-line diagnosis measurement data(insulation resistance, winding resistance, PI, ${\Delta}tan{\delta}$ and PD) on hydro generator(13[kV]) stator windings. These results make good use of managing rotational machines through evaluating the solid insulation condition of stator windings.

• 전기학회논문지
• /
• 제58권4호
• /
• pp.788-794
• /
• 2009

To assess the condition of stator insulation, nondestructive tests were performed on twenty five coil groups and twenty six motors. The stator windings has nominal ratings of 6.6kV and are classified into five coil groups ;one group with healthy insulation and four groups with four different types of artificial defects. After completing nondestructive tests, the AC voltage applied to the stator windings was gradually increasing until insulation failure in order to obtain the breakdown voltage. No.1, No.2 and No.6 of 6.6kV motors failed near rated voltage of 14kV, 8.7kV and 14kV, respectively. The breakdown voltage of three motors was lower that expected for good quality coils(14.2kV) in 6.6kV motors. No.3 and No.6 of 4.16kV motors failed near rated voltage of 5.6kV and 4.2kV, respectively. Almost all of failures were located in a line-end coil at the exit from the core slot. The breakdown voltages and the types of defects showed strong relation to the stator insulation tests such as in the case of AC current, dissipation factor(tan${\delta}$) and partial discharge magnitude.

• 한국태양에너지학회 논문집
• /
• 제37권5호
• /
• pp.65-75
• /
• 2017

In this study, the change of heat loss due to the degree of deterioration of the XPS insulation in KEPCO's office buildings is analyzed. The acceleration aging test of the XPS insulation was carried out according to the test method A of KS M ISO 11561: 2009. The performance of the insulation was analyzed by applying it to the three - dimensional steady state heat transfer analysis program. The acceleration aging test of the XPS insulation, show that the thermal resistance performance decreased by 1.44% at the A regional headquarters, 0.85% at the B regional headquarters, 6.41% at the C branch office, 7.76% at the D regional headquarters, 8.51% at the E branch office, and by 8.54% at the F branch office respectively. Using simulation, we determined that the thermal resistance value of E branch office decreased by 8.04%, while its heat loss increased by 8.52%. At A regional headquarters, the thermal resistance decreased by 1.38%, and the heat loss increased by 1.51%. At D regional headquarters, these value are 6.82% and 7.17%, respectively.