• 대한전기학회:학술대회논문집
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• 대한전기학회 1994년도 추계학술대회 논문집 학회본부
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• pp.45-47
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• 1994

The simulation of reactive power compensation in 5-bus and 25-bus system was conducted using transmission-line loss system identification method. Sensitivities of maximum load-power with respect to reactive power compensation was identified by the simulation. With sufficient reactive power compensation at the first voltage-collapsing load-bus, the first voltage collapse could be prevented until the next voltage-collapsing load-bus lost its voltage stability. And the total compensated reactive power at the first voltage-collapsing bus means reactive power margin of voltage collapse or distance to voltage collapse. This quantity can be useful for determining the size of compensating devices or the site to compensate.

• 한국콘텐츠학회논문지
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• 제7권11호
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• pp.84-93
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• 2007

본 논문은 시스템 버스와 IP로 구성되는 SoC 플랫폼 기반의 설계에서 온칩 버스의 소비 전력을 시스템 레벨에서 빠르고 정확하게 추정하는 방법을 제시한다. 제안된 소비 전력 추정 모델링은 시스템 구조 변화에 따른 버스 시스템의 소비 전력 변화를 직접 예측할 수 있고 이에 따라 시스템 구성을 최적화할 수 있다. 본 논문에서 소비전력 모델링은 크게 두 부분으로 구성된다. 하나는 버스 시스템 구조에 따른 버스 로직들이 사용하는 소비 전력이고, 다른 하나는 데이터 전송시 발생하는 신호 천이에 의한 버스 라인의 소비 전력이다. 본 모델링을 타겟 멀티미디어 SoC인 MPEG 인코더에 적용하여 92% 이상의 정확도를 가짐을 보였다. 제안된 모델링은 고성능/저전력 멀티미디어 SoC 설계에 활용 가능할 것으로 기대된다.

• Journal of Power Electronics
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• 제16권4호
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• pp.1256-1267
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• 2016

Distributed stray inductance exerts a significant influence on the turn-off voltages of power switching devices. Therefore, the design of low stray inductance bus bars has become an important part of the design of high-power converters. In this study, we first analyze the operational principle and switching transient of a T-type converter. Then, we obtain the commutation circuit, categorize the stray inductance of the circuit, and study the influence of the different types of stray inductance on the turn-off voltages of switching devices. According to the current distribution of the commutation circuit, as well as the conditions for realizing laminated bus bars, we laminate the bus bar of the converter by integrating the practical structure of a capacitor bank and a power module. As a result, the stray inductance of the bus bar is reduced, and the stray inductance in the commutation circuit of the converter is reduced to more than half. Finally, a 10 kVA experimental prototype of a T-type converter is built to verify the effectiveness of the designed laminated bus bar in restraining the turn-off voltage spike of the switching devices in the converter.

• International Journal of Control, Automation, and Systems
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• 제3권spc2호
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• pp.376-385
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• 2005

The proliferation of technology has made global conduction of business increasingly dependent upon the availability of reliable power. As a result, alternate power systems are being installed and expanded to protect the broadening scope of critical electrical loads. Bus transfer restores designated critical loads to an alternate source when utility derived service becomes inadequate or goes out of service due to any contingency. This paper describes the practices, requirements and implementation of bus transfer of motor loads to an alternate source of power. A new high-speed automatic bus transfer scheme is proposed which includes the development of a new algorithm for determining the type of bus transfer required and the realization of the scheme by using modem protection devices and intra-substation communication facilities.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2011년도 제42회 하계학술대회
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• pp.1234-1235
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• 2011

A DC Power Distribution Systems(DC PDS) are widely used in telecommunication system, electric vehicle, aircraft, military system, etc. In the DC PDS, DC bus voltage instability may be occurred by the operation of multiple loads such as pulsed power load, motor drive system, and constant power loads. To damp the transients of the DC bus voltage, the Voltage Bus Conditioner(VBC) with the PI compensator is used. In this paper, the validity of the proposed VBC system is verified by PSIM simulation package.

• 한국산학기술학회논문지
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• 제16권4호
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• pp.2737-2743
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• 2015

풍력발전은 풍력단지가 전력계통과 접속되는 모선의 전압을 유지 또는 제어하기 위한 충분한 무효전력을 공급할 수 있어야 한다. 하지만 풍력단지와 계통 접속점(POI - Point of Interconnection) 모선을 연결하는 선로의 무효전력 손실 때문에 풍력터빈의 무효전력공급은 접속점의 전압을 제어하기에는 불충분하다. 이 문제는 접속점에 STATCOM(Static Synchronous Compensator)과 같은 부수적인 무효전력 보상장치를 설치하여 해결할 수 있다. 본 논문에서 제시하는 STATCOM과 Switched-Shunt, 탭변환 변압기와 같은 기존의 무효전력 보상장치의 협조제어를 사용하면 더욱 효과적으로 접속점 모선의 전압을 제어할 수 있다. 본 논문에서 제시한 방법을 이용하여 초기부하에 대하여 임의의 부하 변동률을 가지는 모의 시스템에 적용한 결과 접속점 모선의 전압강하는 60%이상 개선되었고 부하 모선의 전압은 정격전압의 95%이상을 유지하였다.

• 대한전기학회논문지:전력기술부문A
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• 제52권7호
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• pp.429-436
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• 2003

This paper presents a new approach for evaluating the transmission marginal loss factors (MLFs) considering the reactive power. Generally, MLFs are represented as the sensitivity of transmission losses, which is computed from the change of the generation at reference bus by the change of the load at the arbitrary bus-i. The conventional evaluation method for MLFs uses the only H matrix, which is a part of jacobian matrix. Therefore, the MLFs computed by the existing method, don't consider the effect of the reactive power, although the transmission losses are a function of the reactive power as well as the active power. To compensate the limits of the existing method for evaluating MLFs, the power factor at the bus-i is introduced for reflecting the effect of the reactive power in the evaluation method of the MLFs. Also, MLFs calculated by the developed method are applied to energy spot markets to reflect the impacts of reactive power. This method is tested with the sample system with 5-bus, and analyzed how much MLFs have an effect on the bidding/offer price, market clearing price(MCP), and settlement in the competitive energy spot market. This paper compared the results of MLFs calculated by the existing and proposed method for the IEEE 14-bus system, and the KEPCO system.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2005년도 Proceedings of ISRS 2005
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• pp.493-496
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• 2005

The PMU (Payload Management Unit) in MSC (Multi-Spectral Camera) is the main subsystem for the management, control and power supply of the MSC payload operation. The PMU shall handle the communication with the BUS (Spacecraft) OBC (On Board Computer) for the command, the telemetry and the communications with the various MSC units. The PMU will perform that distributes power to the various MSC units, collects the telemetry reports from MSC units, performs thermal control of the EOS (Electro-Optical Subsystem), performs the NUC (Non-Uniformity Correction) function of the raw imagery data, and rearranges the pixel data and output it to the DCSU (Data Compression and Storage Unit). The BUS provides high voltage to the MSC. The PMU is connected to primary and redundant BUS power and distributes the high unregulated primary voltages for all MSC sub-units. The PSM (Power Supply Module) is an assembly in the PMU implements the interface between several channels on the input. The bus switches are used to prevent a single point system failure. Such a failure could need the PSS (Power Supply System) requirement to combine the two PSM boards' bus outputs in a wired-OR configuration. In such a configuration if one of the boards' output gets shorted to ground then the entire bus could fail thereby causing the entire MSC to fail. To prevent such a short from pulling down the system, the switch could be opened and disconnect the short from the bus. This switch operation is controlled by the BUS.

• 전기학회논문지P
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• 제58권4호
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• pp.404-409
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• 2009

A DC power system has many loads with various functions. In particular, these sizable loads take the form of power electronic converters. When they are tightly regulated, the loads appear as constant power loads and result in negative incremental input impedance. Under certain conditions the effect of such loads on the power system is causes instability. In this paper, converter with a large storage capacitor and a lag compensator is proposed as a DC bus conditioner to mitigate the voltage transients on the bus. In addition, the proposed control approach has the advantage of performing both the functions of mitigating the voltage bus transients and maintaining the level of energy stored. Simulation and experimental results showed that the proposed control method was operated well in a small-scale DC power system that contained subsystems with constant power characteristics, such as DC/DC converters and electrical drives.

• ETRI Journal
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• 제28권3호
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• pp.397-400
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• 2006

The multi-layer advanced high-performance bus (ML-AHB) BusMatrix proposed by ARM is an excellent architecture for applying embedded systems with low power. However, there is one clock cycle delay for each master in the ML-AHB BusMatrix of the advanced microcontroller bus architecture (AMBA) design kit (ADK) whenever a master starts new transactions or changes the slave layers. In this letter, we propose an improved design method to remove the one clock cycle delay in the ML-AHB BusMatrix of an ADK. We also remarkably reduce the total area and power consumption of the ML-AHB BusMatrix of an ADK with the elimination of the heavy input stages.