• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 A
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• pp.287-289
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• 1999

This paper proposes mechanism analysis in thermal overload relay. Overload protection performance is closely connected with mechanism of thermal overload relay. In shortage of analytical technique, we have experienced many difficulties in development of thermal overload relay. We applied analytical results to develop optimum thermal overload relay.

• 전기학회논문지
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• 제64권3호
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• pp.473-479
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• 2015

Thermal relays are sometimes used instead of long time overcurrent relays for motor protection. But, it is difficult for any relay design engineer to adequately approximate motor heating curves which represent the average of a difficult-to-define thermal zone. Thermal relays frequently may not provide sufficient protection on heavy overloads. Digital multifunction relays are microprocessor-based devices. These relays offer highly reliable and advanced protection of motors. If a situation can be mathematically described, the microprocessor in a digital relay can be programmed to tackle that problem. Today's motor protection is accomplished with digital protective relays. Digital relays offer additional, highly important features to complement protection. The best way to prevent short in motor is to not overheat and degrade the insulation.

• 조명전기설비학회논문지
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• 제27권5호
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• pp.81-88
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• 2013

A low voltage circuit breaker protects electrical equipments from over current and short faults of system by cutting the power supply. The breaker use a thermal magnetic type trip device from the past. In recent years, electronic type relays are applied due to useful functions and services. The purpose of this development is full digitalizing of relay functions of a low voltage breaker. It includes separation of current sensor from current transformer, digital signal processing, high speed relaying, and voltage measuring for power meter. The suggestions are tested and implemented by making prototype and testing its all relay functions.

• 한국광학회지
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• 제19권2호
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• pp.144-149
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• 2008

대구경 레이저 광집속장치의 쿠데(Coude) 광경로를 구성하는 레이저 반사경들의 레이저 빔조사에 의한 열변형과 이에 따른 광파면 왜곡에 대한 연구를 수행하였다. 쿠데 광경로는 연결거울 3개와 고속조종거울 1개로 구성된다. 반사경은 레이저 빔 파장에 대하여 99.5%의 반사율을 갖으며, 반사경 거울면에 조사된 레이저 에너지는 초당 500 W 정도가 흡수된다. 레이저 빔을 5초 동안 조사하면서 유발된 열하중에 의한 거울의 열 변형과 이에 따른 광파면 왜곡을 분석하였다. 광파면 왜곡은 연결거울의 경우 334 nm_PV, 98 nm rms로 나타났으며 고속조종거울은 $11.5\;{\mu}m$_PV, $3\;{\mu}m$ rms로 나타났다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2015년도 제46회 하계학술대회
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• pp.569-570
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• 2015

Power plants by coal-fired generators in 00 Thermal Power site Division came the most developed environmental system in the world. This paper examined with respect to the setting of the first grade protection relay.

• 한국자동차공학회논문집
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• 제16권2호
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• pp.136-142
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• 2008

Thermal management of a junction box of a passenger car has recently become more challenging due to its smaller size and larger current capacity. Thus, it is essential to perform the thermal optimization of a junction box in its design on an early stage of vehicle design. In this study, 3 dimensional CFD simulation with experimental measurement has been done to study for better thermal management of the junction box. First, the study of thermal characteristics of electric relays in the junction box has revealed that each surface of the relay has very different thermal resistance. In addition, an idea to install a cooling fan on the junction box has been studied and it was found that the forced cooling method was not effective on the system to keep the thermal resistance to the reasonable level of the junction box. Finally, the effect of external flows around the junction box on the temperatures of the relays, fuses, etc. has been studied and the result shows that the installation of the junction box at the proper place in an engine room can avoid any unnecessary overdesign in thermal management.

• 전기학회논문지P
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• 제63권4호
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• pp.322-326
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• 2014

Recently, the LOE(loss of excitation) incidents are occurred in domestic synchronous generator frequently, the synchronous generator protection system has been much attention for the LOE protection of the incidents that threats synchronous generators and power systems. This paper was showed the characteristics and practices of distance relay that widely used LOE protection relaying in generator. Firstly, the operating characteristics and the impedance locus for LOE of the generator protection were introduced. Even if the conventional simulation program is used for modeling, but it is difficult to implement a LOE modeling and simulation of synchronous generator. So, the LOE relay operation data collected from thermal power plant and nuclear power plant in real fields were analyzed. By reviewing the applications of GE Mho relays, the reliability of LOE for synchronous generator protection in domestic were improved.

• 한국산업융합학회 논문집
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• 제20권5호
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• pp.419-424
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• 2017

The purpose of this study is to develop a virtual testbed capable of predicting the functional performance of a linear electromagnetic actuator for a high voltage relay in order to reduce its development costs and time. The virtual testbed is defined by a multiphysics coupling approach in order to consider the complex interactions of multi-domains such as the solenoid model of electromagnets, the mass-spring-damper model of mechanical systems, the electric circuit model for an external control unit, and the thermal model for predicting temperature variations. The performances of the existing high voltage relay were estimated by the virtual testbed, and then the effectiveness and validation of the proposed testbed were discussed in comparison with the experimental test results. This study showed that the virtual testbed can be applied in design, optimization, and investigation of high voltage relays.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2000년도 제15차 학술회의논문집
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• pp.62-62
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• 2000

An auto-tuning PID controller which is adequate for temperature control is developed based on relay-control and pole-placement Using the critical frequency which is obtained from relay-control parameters of assumed model are identified. Pole/zero-placement PID controller is designed for the identified model. The desired pole/zeros are determined so that the closed-loop has overshoot free step response. The developed auto-tuning PID controller was successfully applied to the temperature control of RTP.

• 전자공학회논문지SC
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• 제49권1호
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• pp.80-87
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• 2012

본 논문에서는 열상장비의 광 검출기에서 검출된 미약한 전기적 신호를 영상신호처리를 하기 위한 신호로 증폭을 해 주는 전단 증폭부의 성능 검사용 ATE(Automatic Test Equipment)를 개발하였다. 기존 ATE 장비는 주로 반도체 소자 양품검사 분야에서 활발히 개발되고 있었으나 최근에는 장비의 성능검사 분야에서도 연구되고 있다. 그러나 열상장비 성능검사 분야의 ATE 에 대한 연구는 다른 분야에 비해 미진하여 우리군의 핵심적인 감시 장비인 열상장비는 정비가 제한되었다. 이에 따라 본 논문에서는 새로운 열상장비 분야의 ATE 연구가 필요하여 전단증폭부 및 열상장비의 다른 회로카드의 범용적인 개발이 가능하도록 Matrix Relay를 개발하였다. 개발된 ATE로 전단증폭부의 증폭도를 측정한 결과 증폭 전압은 평균 2.71 Vpp로써 이론적인 분석 범위 내에 있음이 확인되어 개발된 ATE가 우수한 성능임이 검증되었다.