• 조명전기설비학회논문지
• /
• 제29권7호
• /
• pp.47-53
• /
• 2015

As the industrial development in Korea, the power demand is rapidly increased. The power system has been extended and complicated to meet the power demand. However, the fault current increases because the structure of power system reduces the equivalent impedance. One of the solutions to reduce the fault current is Superconducting Fault Current Limiter(SFCL) and the researches of SFCL application have much conducted. In this paper, we used the Circuit Breker Burden Index(CBBI) to select application location of SFCL because the CBBI may consider a fault current of each line. In addition, this paper divided the weight factor used to calculate the CBBI on a case by case basis and analyzed this characteristics through experiment.

• 한국산업융합학회 논문집
• /
• 제5권3호
• /
• pp.255-260
• /
• 2002

Recently, the occurrences of electrical fire have been suppressed by an earth leakage breaker(ELB), a no fuse breaker(NFB) and a fuse in case of an earth leakage, a short circuit and an over current. But it is impossible for the ELB to break the circuit in the case of the failure of pressure contacts on connecting points and the momentary short circuit. Therefore, it is require to study the constructive problem of the ELB. In this paper, we have developed the auxiliary control device, electrical fire prevention control device(EFPCD), of the ELB. And we have tested the operation characteristics of the ELB according to the load(R, L) As a result of this experiment, we could prevent the electrical fire due to the spark and the overheat occurring in the failure of pressure contacts on connecting points and the momentary short circuit.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2005년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
• /
• pp.61-63
• /
• 2005

In this paper, a new type of permanent magnetic actuator (PMA) with multi-stage coils is proposed. Although the conventional type of PMA has many advantages, it cannot be applied in the high voltage circuit breakers due to its short stoke length. The new type of PMA has long stroke length by using multi-stage coils, so it can be applied as an actuator for the high voltage circuit breakers. Dynamic characteristics are calculated by the finite element method (FEM), equation of electric circuit and dynamic equation. The position of plunger and the current of coils in case of the actuator applied in 38kV, 40kA vacuum circuit breaker are presented.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2003년도 추계학술대회 논문집 전기기기 및 에너지변환시스템부문
• /
• pp.12-14
• /
• 2003

This paper presents the small current interruption capability of $SF_6$ puffer circuit breaker considering pre-condition. Firstly, the change of dielectric strength of the 3 breakers was compared with testing breakers as clean contacts and eroded contacts after 3 shots of 760 according to new IEC 62271-100 standard. Also the dielectric strength curve of each model was calculated through flow and electric field simulations. From these results, we could modify the empirical equation, being used to predict the dielectric strength of small current interruption capability, considering the effects of pre-condition.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2008년도 제39회 하계학술대회
• /
• pp.91-92
• /
• 2008

The rating of a circuit breaker depends not only on the interrupting current but also on a transient recovery voltage (TRV). To achieve a successful interruption, the circuit breaker must withstand the TRV. A superconducting fault current limiter (SFCL) is a device that limits the fault current fast and effectively without having high impedance during normal operation of the power system. Therefore, we studied the influence of the TRV according to the application of a resistive type SFCL in distribution system. This paper analyses the influence of the TRV for various application position of the resistive SFCL. The distribution system and the resistive SFCL were modeled by using EMTP-RV (Electromagnetic Transient Program - Restructured Version)

• 조명전기설비학회논문지
• /
• 제29권8호
• /
• pp.49-54
• /
• 2015

Molded Circucit Breaker(MCCB) is a most widely used device to protect loads from the over-current in low power level distribution system. When the MCCB interrupts the over-current, the arc discharge occurred between fixed contact and moving contact to create hot gas. By the Lorentz force due to arc current, the occurred arc is bent to the grids. The grids extend and cool and divide it for arc extinguish. In the majority cases, the MCCB protects loads by interrupting the over-current successfully but in some cases the re-ignition is occurred by hot-gas created during process of interruption. The re-ignition arises when the recovery voltage(RV) is more higher than the recovery strength between contacts and it leads to interruption fault. Therefore to find out the dielectric recovery characteristics of protecting device has a great importance for preventing interruption fault. In this paper, we studies measurement method of the dielectric recovery characteristics considering inherent attribute of the MCCB. To measure the dielectric recovery characteristic of MCCB, we makes an experiment circuit for applying the over-current and the randomly recovery voltage. The measurement methode to find out the dielectric recovery voltage of the MCCB was established and the result was based on experiment results.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
• /
• 제55권10호
• /
• pp.521-527
• /
• 2006

After various measuring methods and system were investigated, Rogowski colis for the measurement of parameters in current zero region were designed and manufactured. Using the Rogowski coils and a 38kV 40kA VCB (vacuum circuit breaker), at last the post-arc current has been successfully measured firstly. It was found that the Rogowski coils used in this study have good characteristics and propriety to measure the parameters of current zero. We realized that the data processing for evaluating the post-arc current from the experimental results needs much more careful attention than that for building the measuring technique and system. The magnitude of post-arc current and the falling time of it to zero are proportioned to the rate of current di/dt. The magnitude of post-arc currents were around $1{\sim}3A$ to the interruption current of $20{\sim}30kA$ in the model VCB.

• 조명전기설비학회논문지
• /
• 제16권6호
• /
• pp.137-144
• /
• 2002

배선용 차단기(MCCB)는 신속한 고장전류 차단과 전원시스템의 안정성을 확보하기 위해 배전시스템에 폭넓게 사용되고 있다. 본 논문에서는 MCCB의 소호부 형상에 따른 차단성능을 파악하고 이를 통해 성능향상을 꾀하고자 3차원 자계해석을 이용한 차단성능 평가해석기법을 개발하고, 개발한 평가해석기법을 각 모델 차단기에 적용한 바를 기술하였다. 또한, 소호부내 3분할 다단형 아크런너을 구성하여 불연속 통전경로를 형성함으로 해서 차단성능에 미치는 영향을 살펴보았다. 끝으로, 이상의 연구내용을 토대로 새로운 소호부 형상을 고안하여 국내 최초로 460［V］/225［A］/50［kA］ 대전력 단락시험에 성공한 결과를 제시하였다.

• Journal of Electrical Engineering and Technology
• /
• 제12권1호
• /
• pp.182-188
• /
• 2017

An arc eliminator allows a surge current bypass rapidly into the earth to facilitate the circuit breaking process and increase the stability of the load circuit. Thomson coil actuator (TCA) is a type of actuator that can function as an arc eliminator. The TCA has a simple structure and significantly rapid speed compared to the other types of actuators. In this paper, significant variables, which have a dominant effect on the performance of the TCA, are investigated in detail. Using these variables and an optimization algorithm, an optimal design strategy for the TCA is proposed in this research. The efficacy of the proposed optimal design strategy and the feasibility of the application of the designed TCA for a high power circuit breaker as the arc eliminators are validated through the experiment.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1996년도 하계학술대회 논문집 A
• /
• pp.80-82
• /
• 1996

This paper deals with the effects of the volume of thermal expansion chamber on the interrupting performance in thermal expansion type 25.8kV 25kA gas circuit breaker. Model interrupters with 5 type thermal expansion chamber were designed and manufactured. Short-circuit tests were carried out for those model interrupters with 25kA breaking current. Pressure rise in the expansion chamber were measured and compared with the calculated one which was obtained from a self-developed program in our team. The analysis on the interrupting performance of each model interrupter has been done on the base of the short-circuit test results.