• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 제37회 하계학술대회 논문집 A
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• pp.329-330
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• 2006

The purpose of this paper is to compensate the voltage drop of the power system in the AC Electric Railway Systems. Reactive power compensation is often the most effective way to improve system voltage drop. The suitable modeling of the electric railway system should be applied to the EMTP. the dynamic characteristics of 3-Phase Induction Motor in Electric Railway Systems is considered for precise modeling. it is shown through EMTP simulation using EMTP MODELS that voltage drop can be compensated effectively by STATCOM.

• 전기학회논문지P
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• 제67권3호
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• pp.155-159
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• 2018

Recently, the expansion or establishment of facilities for the logistics system is increasing. Conveyor facilities play a major role in sorting and transporting logistics. Induction motors are widely used for the operation of these conveyor systems. In the logistics system, a large number of induction motors are used. These motors have a considerable distance from the power source side and have a low power factor. The installation position for the power factor compensation of the induction motor is very important. Since the voltage drop depends on the length of the line, it is an important parameter in capacitor capacity determination for power factor compensation. The capacity of the capacitors installed to compensate the power factor of the inductive load should be designed to the extent that self-excitation does not occur. In this study, we analyze the method of compensating the proper power factor considering the voltage drop and the installation position of the induction motor in the logistics system.

• 전기학회논문지
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• 제64권8호
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• pp.1202-1206
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• 2015

The induction generator has many advantages compared to the synchronous generator in terms of cost and maintenance. So squirrel cage induction generator has been recently supplied in small hydroelectric power station. Squirrel cage induction generator generates a high inrush current at the grid-connection. This high inrush current causes a voltage drop on the grid. In order to increase the supply of the induction generator, it is very important to find the method of reducing inrush current and voltage drop.

• 전기학회논문지P
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• 제64권2호
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• pp.62-66
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• 2015

Induction generator is easy to durability and maintenance than the synchronous generator. So, recently Induction generator has been widely applied to small-scale hydroelectric power plant. When the rotor is operating faster than synchronous speed, induction machine can generate electric power. Induction generator has a large inrush currents, such as the starting current of the induction motor. Induction motor has been designed a variety of rotor shape in order to reduce starting current. Since the occurrence of high inrush current cause a voltage drop to the system, it will need to reduce possible. Because the starting current of the squirrel-cage induction motor varies in accordance with the rotor shape, it is necessary to analyze the magnitude of inrush current in order to apply to the generator. In this study, we analyzed the inrush current and the voltage drop caused in accordance with the rotor shape of 1500kw induction generator.

• 한국전기전자재료학회논문지
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• 제19권10호
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• pp.912-917
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• 2006

In this paper, Trench emitter electrode IGBT structure is proposed and studied numerically using the device simulator, MEDICI. The breakdown voltage, on-state voltage drop, latch up current density and turn-off time of the proposed structure are compared with those of the conventional trench gate IGBT(TIGBT) structures. Enhancement of the breakdown voltage by 19 % is obtained in the proposed structure due to dispersion of electric field at the edge of the bottom trench gate by trench emitter electrode. In addition, the on-state voltage drop and the latch up current density are improved by 25 %, 16 % respectively. However increase of turn-off time in proposed structures are negligible.

• 한국전기전자재료학회논문지
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• 제25권5호
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• pp.340-344
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• 2012

Protected Circuit Module protects battery from over-charge and over-discharge, also prevents accidental explosion. Therefore, power MOSFET is essential to operate as a switch within the module. To reduce power loss of MOSFET, the on state voltage drop should be lowered and the switching time should be shorted. However there is trade-off between the breakdown voltage and the on state voltage drop. The TDMOS can reduce the on state voltage drop. In this paper, effect of design parameter variation on electrical properties of TDMOS, were analyzed by computer simulation. According to the analyzed results, the optimization was performed to get 65% higher breakdown voltage and 17.4% on resistance enhancement.

• 에너지공학
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• 제10권4호
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• pp.310-317
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• 2001

동일한 변압기에서 인출된 서로 다른 선로중 하나의 선로에서 고장이 발생하는 경우 다른 선로에서는 순간적인 전압강하 현상을 경험하게 된다. 이렇게 발생되는 순간전압강하 현상은 비록 선로의 계전기에 의해 사고가 제거되기까지의 짧은 기간동안 지속되지만 기기에 따라서는 막대한 피해를 유발할 수 있다. 예로서, 반도체 공장의 정밀 공정중 순간전압강하가 발생하면 공정이 중단되거나 공정의 재시작등으로 인하여 a가대한 경제적 손실을 유발하게 된다. 또한 각종 정밀기기 등에는 기기의 수명저하를 유발하기도 한다. 본 논문에서는 전력계통에 직렬로 연결되는 인버터 시스템을 이용하여 계통에 전압을 주입함으로서 순간전압강하를 보상할 수 있는 시스템에 관하여 연구하고 운전 알고리즘을 제시하였다. 컴퓨터 시뮬레이션과 실험을 통하여 제시한 운전알고리즘의 유효성을 입증하였다.

• 한국안전학회지
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• 제30권3호
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• pp.26-31
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• 2015

This paper describes the characteristics of voltage drop and thermal for poor connection on electrical connector of circuit breaker in control box of small size pulverizer. In order monitor, we did the changes of RMS in voltage and temperature value with video and made normal state over $2.5N{\cdot}m$ and poor connections state below $0.2N{\cdot}m$ by screw gage. In case of voltage signal, the voltage drop was increased when the current was increased due to poor connections. In case of temperature signal, the temperature difference indicates ten times at 5A and fourteen times at 15A in the normal state. According to increase thermal energy, the insulation of electrical wiring and connector of circuit breaker can be carbonized. The results of this study will be useful to the development of preventive devices and system for electric fire by poor connection at small size pulverizer.

• 조명전기설비학회논문지
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• 제28권6호
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• pp.45-51
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• 2014

Synchronous generators and induction generators are mainly used in hydroelectric power generation. Synchronous generator is mainly applied to large hydroelectric plants but induction generator is applied to the small hydro power plants. Stability of induction generator is slightly less than the synchronous generator. However, induction generator has many advantages rather than a synchronous generator in terms of price and maintenance. So Induction generator is used primarily in small hydroelectric power station less than 1,000kW recently. Squirrel cage induction generator generates a high inrush current at the grid-connection. This high inrush current causes a voltage drop on the grid. In order to reduce the voltage drop and to analyze the power flow, the analysis for operating characteristics of the induction generator should be reviewed in advance. In this study, we analyzed the voltage drop and power flow analysis when a 1500kW induction generator is connected to the grid. The voltage drop is slightly higher than the acceptable range of distributed power supply voltage and the power flow of the generator is performed well.

• 한국정보통신학회논문지
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• 제12권10호
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• pp.1835-1839
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• 2008

파워 매니지먼트는 휴대용 전자 기기에서 매우 중요한 역할을 한다. 휴대용 전자 기기는 배터리의 수명을 증가시키기 위해 LDO와 같은 파워 효율적인 파워 매니지먼트를 요구한다. 그래서 배터리 전원을 사용하는 휴대폰, 카메라 레코더, laptop, 자동차 전장용, 산업용 기기 등의 응용에서는 배터리의 전압변동이 크기 때문에, 배터리 전원을 그대로 사용하지 않고 내부회로의 전원을 제공해 주는 LDO를 이용한다. 레귤레이터는 배터리 전원전압 보다 낮은DC전압을 내부회로에 제공하며, 큰 변동을 보이는 배터리 전압에 관계없이 일정한 DC전압을 제공할 수 있다. 본 연구에서는 0.18um CMOS 공정기술로 제작된 온칩 LDO의 파워 세이브 모드 전류 특성과 IR-Drop 특성을 파악해 보았다.