• 한국군사과학기술학회지
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• 제17권4호
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• pp.404-412
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• 2014

We proposed a design method for squib current supply & interlock circuits in guided-missile fire control systems. In order to design squib current supply circuits, various missile squib loads including line resistance and squib devices have to be considered in advance minimizing probability of redesign of circuits and reducing the development cost by implementing the most proper squib current supply circuit. Also, we presented a hardware interlock logic instead of the commonly used software safety logic to improve the safety of guided-missile fire control systems. The proposed squib interlock circuit enhances safety requirements of guided-missile fire control systems. We confirmed that simulation and measurement results of the proposed design method are the same as theoretical analysis results.

• 전기전자학회논문지
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• 제23권1호
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• pp.107-111
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• 2019

FPD(Flat Panel Display) WET(습식) 장비의 히터 사용은 필수로 사용된다. 히터 사용에 따른 단선과 과열로 인한 전기사고가 다발하여 안전적인 전기 계통도 및 인터락이 필요하다. 따라서 본 논문에서는 FPD WET장비에 들어가는 전기 계통도 및 인터락을 제안하였다. 레벨센서, 과열방지기, SSR heater sink와 같은 하드웨어 인터락을 넣었으며, 전기 계통도로써는 ELB-MC-SSR-EOCR-Heater로 구성되어 있다. 인터락 발생시 마그네틱 컨텍터(MC)가 오프되어 Heater의 전원을 차단하는 방식이다. 전기적 과전류 보호장치인 EOCR 과전류, 부족전류, 단선 체크를 하면서 히터에 이상 있을 시 MC를 차단하는 인터락이 구성되어 있다. 이러한 회로 구성 및 인터락은 WET 장비 뿐만 아니라 히터가 들어가는 어떠한 장비에도 유용할 것으로 보인다.

• 한국안전학회지
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• 제29권4호
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• pp.54-60
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• 2014

This paper describes electric shock accidents on a 4.16 kV class circuit breaker for power plant. Electric shock accidents mostly involve damage of human life, in comparison with electrical fire, rate of human death tend to be higher in electric shock accidents. Specially, in a high voltage facilities rate of human death comprised about 43.7% by electric shock accidents. If electric shock accidents happen in a 4.16 kV class circuit breaker for power plant, then the power plant discontinue power production. Electric shock accidents in a power plant have a great ripple effect such as an electric power shortage. In this paper, we analyzed electric shock accidents on a 4.16 kV class circuit breaker for power plant. From the analysis results, we confirmed a cause of electric shock accidents on a 4.16 kV class circuit breaker, it happened by defect of interlock equipment or occurrence of breakdown between first feeder contactor and shielding plate. In order to reduce electric shock accidents on a 4.16 kV class circuit breaker, the power plant should consider improvement of interlock equipment and insulation of feeder contactor in circuit breaker.

• Journal of Electrical Engineering and Technology
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• 제1권3호
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• pp.359-365
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• 2006

Since the start of the KSTAR (Korea Superconducting Tokamak Advanced Research) project, Instrumentation and Control (I&C) of the Neutral Beam Test Facility (NB-TF) has been striving to answer diverse requests arising from various facets during the project's development and construction phases. Hard-wired electrical circuits have been designed, tested, fabricated, and finally installed to the relevant parts of the system. In relation to the vacuum system I&C, controlling functions for the rotary pumps, a Roots pump, two turbomolecular pumps, and four cryosorption pumps have been constructed. I&C for the ion source operation are the temperature and flow rate signal monitoring, Langmuir probe signal measurements, gradient grid current measurements, and arc detector circuit. For the huge power system to be monitored or safely operated, many temperature measurement functions have also been implemented for the beam line components like the neutralizer, bending magnet, ion dump, and calorimeter. Nearly all of the control and probe signals between the NB test stand and the control room were made to be transmitted through the optical cables. Failures of coolant flow or beam line vacuum pressure were made to be safely blocked from influencing the system by an appropriate interlock circuit that will shut down the extraction voltage application to the system or prevent damages to the vacuum components. Preliminary estimation of the beam power through the calorimetric measurement shows that 87.9% of the total power of the 60kV/18A beam with 200 seconds duration is absorbed by the calorimeter surface. Most of these I&C results would be highly appropriate for the construction of the main NBI facility for the KSTAR national fusion research project.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2002년도 추계학술대회 논문집(II)
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• pp.995-1000
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• 2002

This paper presents general concept of DC switch gear(DCSWGR). Normally, DCSWGR consist of Digital protection unit(DPU), High Speed Circuit Breaker(HSCB), Disconnect Switch (DS), Programmable Logic Control(PLC), Auxiliary Relays and etc. Most of the components has its special characteristics and their interface between each others are various and complex. In this paper every constituent general design are preceded and interface between each component are examined. And also DCSWGR operation logic with logical diagram including interlock signal are introduced.

• Nuclear Engineering and Technology
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• 제53권1호
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• pp.121-130
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• 2021

Cascading failure is the main cause of large blackouts in electrical power systems; this paper analyzes a cascading failure in Hanbit nuclear power plant unit two (2) caused by a circuit breaker (CB) operation failure. This malfunction has been expanded to the loss of offsite power (LOOP). In this study, current practices are reviewed and then the methodologies of how to prevent cascading failures in protection power systems are introduced. An overview on the implementation of IEC61850 GOOSE messaging-based zone selective interlocking (ZSI) scheme as key solution is proposed. In consideration of ZSI blocking time, all influencing factors such as circuit breaker opening time, relay I/O response time and messages travelling time in the communication network should be taken into account. The purpose of this paper is to elaborate on the effect of cascading failure in NPP electrical power protection system and propose preventive actions for this failures. Finally, the expected advantages and challenges are elaborated.

• 에너지공학
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• 제24권3호
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• pp.27-33
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• 2015

Recently, global warming has been accelerated due to air pollution and air pollutants are coming from the exhaust of the ICE vehicles, which are gradually increasing in number globally. That is why all the countries in the world are striving to reduce pollutant emissions of automobiles by strengthening regulations on air pollution. To comply with the regulations, the auto industry came up with hybrid vehicles, which have features of both ICE vehicles and electric vehicles. Hybrid vehicles show improvements in emissions, fuel efficiency, as well as functions as electric vehicles. This study aims to show possible troubles that occur at times of damages in high-voltage systems, and to suggest responsive measures.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1987년도 정기총회 및 창립40주년기념 학술대회 학회본부
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• pp.408-411
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• 1987

We have designed the power supply of an 120W $CO_2$ Laser for non-metal material processings. High voltage is automatically controlled by means of thyristor triggered phase control. Pulse and C.W. mode are selectively generated by means of discharge current control. It is possible to interface this system with other Numerical Controller. Also, safety interlock circuit is incorporated in this system.

• 대한전기학회논문지
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• 제39권3호
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• pp.273-280
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• 1990

To prevent the shoot-through phenomena in a PWM inverter, a short dead time is usually provided between a pair of switching transistors in the same leg of the inverter. In this approach, the amount of the dead time is designed to meet the worst case condition of the inverter transistors and the base drive elements. So, in normal cases, relatively large portion of the dead time is unnecessary and it results in an undesirablecurrent waveform distortion and generates ripple torque on the motor shaft. In this paper, a new base drive method to remove the undesirable portion of the dead time is described. The method senses the transistor on/off states to interlock the other transistor of the leg without the external dead time. Also, for the transistors of large current rating, the Darlington drive circuit is combined to the proposed method and is tested to verify the effectiveness. The experimental results of the proposed method are described and compared with those of the conventional dead time method.

• 한국화재소방학회논문지
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• 제26권3호
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• pp.29-34
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• 2012

본 논문에서는 소방전원 및 소방전원 부족시 용량 보완을 위한 인터록 시스템의 한계점 등을 분석하고 소방전원 보존형 발전기(RFP)의 작동방법 등을 제시하여 화재와 같은 상황에 효율적으로 대응할 수 있는 방법을 제시하는데 있다. 소방전원보존형 발전기에서 일괄제어방식은 발전기에 과부하가 걸리면 소방전원보존용 제어기에서 신호를 발신하여 소방부하는 남겨두고 비상부하용 주차단기를 일괄 차단하고, 발전기가 마지막까지 소방부하에 전원이 공급되도록 한 시스템이다. 순차제어방식은 과부하가 걸리면 소방전원보존용 제어기에서 1차 신호를 발신하여 설정된 비상부하의 1단계 부하를 차단한다. 그리고 지속적인 감시 상태에서 소방부하가 증가하여 발전기가 다시 과부하가 걸리면 제어기에서 2차 신호가 발신하여 비상부하의 2단계 부하를 차단하는 시스템이며 각각의 작동 상태를 표시하는 표시장치를 가진다.