• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.13 no.6
• /
• pp.502-508
• /
• 2000

In order to detect the partial discharge with the metallic particle in GIS the AE(Acoustic Emission) sensor was designed and simulated by ANSYS 5.5 and manufactured as the coupled vibration mode. The measured resonant frequency and the maximum sensitivity frequency of three coupled AE sensors were as follows ; 147.88 kHz in 8.1mm $\Phi$$\times$8.1mm 128.82 kHz and 58.8 kHz in 9.5 mm$\Phi$$\times$9.5mm, 85.22 kHz and 32.6 kHz in 14.3 mm$\Phi$$\times$14.3 mm, resonant frequency of the AE sensor. The AE sensor of 9.5 mm$\Phi$$\times$9.5mm responded higher than the other coupled vibration mode AE sensor at the partial discharge detection in GIS.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2000.05b
• /
• pp.216-221
• /
• 2000

This paper describes the analysis results on the PT ferroresonance at 154 kV GIS (gas Insulated substation by EMTP(Electro- magnetic Transient Program). We had simulated the PT ferroresonance between a potential transformer(PT) and an open circuit breaker's grading capacitance. The ferroresonance leads to very large power frequency overvoltages on PT bus and subsequent insulation failure. The large power can be supplied to the PT by the high voltage on the opened circuit due to the grading capacitance and equivalent capacitance of the buses during the ferroresonance. The damping circuit connected on the secondary winding were considered in the model. The actual countermeasure include a saturable inductor and a resistor series-mounted, but the 2 ohms of damping resistance was used in the computationl model.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.20 no.10
• /
• pp.901-906
• /
• 2007

In this study, we measured the partial discharge phenomenon of inside the closed switchgear, using ultra wide band antenna. The characteristics of $\Phi-q-n$ in the normal state are stable, and confirmed at less than 0.01, but in proceeding states, about 2 times larger. And in the abnormal state, it grew hundreds of times larger compared with normal state. According to K-means analysis, if slant of discharge characteristics is a straight line close to "0" and standard deviation is small, it is in a normal state. However if we can find a peak from K-means clusters and standard deviation to be large, it is in an abnormal state.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2010.06a
• /
• pp.283-283
• /
• 2010

Smart street light controller is a product with advance micro controller base for energy saving in conventional street lighting systems. Intelligent Street light controller are specially developed for automation and energy saving in conventional street light systems and lighting systems. It is so designed that it operates on sunrise & sun set timings according to longitude of particular location with facilitate to set month wise civil twilight timings to cope up with all seasons. Dimming (Power down) mode selection switch on/off at fixed times with relay or contactor. Night dimming, staggering and intelligent control reduces burn hours and increases the lifetime of lamps with about 30% and low annual operating cost type base are among the most inexpensive wireless technologies available. Low initial costs As PLC wireless, there is no need to establish cable connection.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.25 no.6
• /
• pp.467-473
• /
• 2012

A functionally graded material (FGM) spacer, which the distribution of dielectric permittivity inside an insulator changes spatially, can considerably reduce the electric field concentration around a high-voltage electrode and along the gas-insulator interface when compared to a conventional spacer with a uniform permittivity distribution. In this research, we propose the FGM spacer with an elliptical permittivity distribution instead of that with a distribution of dielectric permittivity varying along a radial direction only in order to improve efficiently the insulation capability. The optimal design of the elliptical FGM spacer configuration is performed by using the response surface methodology (RSM) combined with the steepest descent method (SDM).

• 전기의세계
• /
• v.25 no.4
• /
• pp.12-16
• /
• 1976

Thyristor등의 반도체등의 전자장치를 사용하여 전력의 변환, 제어 및 개폐등을 행하는 기술분야를 1962년 Storm씨가 Solidstate Power Electronics라고 부르기 시작한 이래 급속한 발전을 이룩하여 왔음은 다 아는 사실이다. Storm씨는 1950년대에 전력제어를 위한 장치로써 가포화 리액터를 이용한 자기증폭기의 개발과 이론전개에 공헌한 분으로 전력용 반도체 소자의 개발의 필요성과 그 응용면의 가치를 가장 절실히 느끼고 있었다. 이는 자기증폭기가 무접점의 자기적 switch가 기계적인 switch에 비하여 응답속도가 빠른 것은 사실이나 400Hz 이상에서는 그 한계성을 가져왔기 때문에 새로운 소자 즉 전자적 전력 switch의 개발의 필요성을 당연하였던 것이다. 이상과 같은 소자들은 동작면에서 전압의 증폭을 대상으로 한것이 아니고 전류의 단속에 의한 전력변환을 목적으로 한 것이라고 볼 수 있다. 즉, 단위전하의 에너지로 표시되는 전압의 조정이 아니고 전하의 수를 조정하는 전류조정작용을 가지 소자라는 점에서 이들을 이용한 장치는 전류제어형이어야만 할 것이다.

• Electrical & Electronic Materials
• /
• v.9 no.4
• /
• pp.385-395
• /
• 1996

이 논문은 금속성 돌기물에 의한 불평등전계중에서의 비진동성과 진동성 임펄스전압에 의한 SF$_{6}$ 가스의 절연파괴 특성에 대해 기술하였다. 절연파괴전압-시간특성을 가스압 0.1-0.5MPa의 범위에서 정.부 극성의 전압을 인가하여 측정하였으며, 그리고 50.ohm.분류기를 통해서 전구방전 전류를 관측하였다. 가스압력에 의한 리이더 진전시간의 의존성도 측정하였다. 스트리머 코로나에 의해 발생하는 공간전하에 의한 국부전계강화는 시험갭의 전기적 절연파괴에 영향을 미치는 것으로 판명되었다. 절연파괴는 초기 스트리머 코로나로부터 발단되어, 국부전계강화에 의한 리이더진전으로 이루어진다.

• Proceedings of the KIEE Conference
• /
• 2000.07b
• /
• pp.940-942
• /
• 2000

전기설비에 있어서 저압회로의 과전류 보호기기로는 배선용 차단기, 기중 차단기, 한류 퓨즈, 전자 개폐기 등이 있으며, 이중 배선용 차단기의 중요한 차단원리인 한류차단원리 및 현상에 대해 상세한 분석이 필요하다. 단락이 발생하면 상당히 큰 단락전류가 흐르게 된다. 이 단락전류를 차단하는 경우 단락전류를 그대로 흐르지 않게 하여 본래의 단락전류를 작게 제어하면 차단시의 에너지는 작아진다. 본래의 단락전류를 작게 억제하여 차단하는 방법을 한류차단방식이라 하며 이러한 기구를 한류기구라 한다. 한류차단방식을 채용함으로써 동일 치수의 차단기라면 보다 큰 단락전류를 차단하는 것이 가능하다. 여기서는 한류차단특성의 이론적 해석과 단락전류에 의한 전자기적 영향, 기계적인 영향, 열적인 영향을 설명하고 이러한 영향을 최소화하기 위한 한류차단 원리 및 방법을 설명하고 분석하고자 한다.

• Journal of the Korean Institute of Telematics and Electronics
• /
• v.7 no.2
• /
• pp.1-12
• /
• 1970

In this paper, theoretical and experimental study about the light modulation at X-band(9375MHz) micro wave, using the linear electro-optic effect, has been described. The electro-optic crystal, KDP (potassium dihydrogen phosphate)is used for modulator crystals which is composed resonated modulator. Output performances of modulated wave through movable short positions are presented. It was critically respond from 2. And the output modulated intensity was compared with theoretical curve. Consequently, in spite of many problems remain yet, most promissing and more sucessful modulator configurations are compleely given.

• Journal of the Korean Institute of Telematics and Electronics B
• /
• v.32B no.11
• /
• pp.1455-1463
• /
• 1995

A new automatic tracking & recognition algorithm which decides the opening & the closing states of subject's eye and isn't affected by the subject's background is proposed. And it was tested in circumstances in which subject's background was not restricted using the developed system, ATRS(Automatic Tracking & Recognition System). The significant characteristic of the ATRS is new movement detection of object that is a body in motion with accelated velocity and it doesn't need any extra hardware except a formal CCD camera and an image grabber but it works so well and so fast. The ATRS would be particularly well suited to a way of communications of patients in a hospital, who can not communicate otherwise.