• Proceedings of the KIEE Conference
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• 2006.11a
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• pp.360-362
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• 2006

가용송전용량(Available Transfer Capability : ATC) 계산을 위해 우선 견정해야할 요소는 총 송전용량(Total Transfer Capability : TTC)이며 이는 일반적으로 열, 전압, 안정도 한계치에 의해 결정된다. 국내 계통의 송전선로 길이를 고려할 때, 이 세 가지 한계치 중 열 정격은 TTC 결정에 가장 큰 비중을 차지하는 요소이다. 따라서 본 논문은 열적 한계치에 동적 송전용량(Dynamic Line Rating : DLR)의 개념을 도입 하여 TTC를 결정하는 새로운 접근법을 제안한다. 이 방법은 기존의 방법에 비해 주변 환경의 물리적 변화에 따른 정확한 계산 결과를 제공함으로서, 실제 사용가능한 용량을 평가한다. 마지막으로 제안하는 방법의 유용성을 보이기 위해 IEEE-24 모선 RTS를 이용하여, 기존의 방법과 제안하는 방법을 비교하였다.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.12
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• pp.177-183
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• 2010

Overhead transmission lines in domestic area have been built by several different design standards of dip and ground clearance. This paper describes an experimental study for evaluating load capacity and dip margin in overhead transmission lines. Such design standards for selection of overhead transmission conductors, dip and ground clearance, as well as electrical equipment technical standard are discussed. Based on daily load and weather data, several characteristics such as line utilization factor, load factor, conductor temperature and dip, etc. are analyzed, and compared with the specified levels of design standards. As a result, it is verified that DLR method can be a clue of the solving of the problem, for occurring in old transmission conductors which may be rarely operating below standards.

• Journal of Power Electronics
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• v.1 no.1
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• pp.48-55
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• 2001

This paper describes a switching-level simulation model and scaled hardware model for SSSC, which is useful for analyzing the dynamic interaction between the SSC and the power transmission system. A detailed simulation model with EMTP was developed to verity the SSSC operation with control system, and its increasing capability of power transmission through the line for a typical one-machine infinite-bus system. The simulation results of the developed model are compared with the experimental results froma scaled model fo 2KVA rating for evaluation the whole system operation.

• Proceedings of the KIEE Conference
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• 2005.07a
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• pp.583-585
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• 2005

선로의 DLR을 추정하는 방식 중에서 간접도체 방식은 시험도체가 선로의 도체와 유사한 환경에 직접 노출되어 있어서 일사량, 풍속, 풍향 통 측정감도가 낮은 요소들을 직접 측정하여 사용하지 않아도 이들의 종합적인 효과를 반영할 수 있는 장점이 있다. 본 논문에서는 간접도체 방식에 의한 DLR 추정 알고리즘을 보이고 가열도체와 비가열도체를 사용한 실험을 통하여 추정 풍속 및 DLR 산정결과가 실측 풍속 및 기상요소로 추정한 값들과 거의 일치함을 보임으로써 DLR 산정 방식으로서 간접도체 이용의 타당성을 제시하였다.

• Proceedings of the KIEE Conference
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• 2005.07a
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• pp.586-588
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• 2005

도체의 허용전류를 추정하기 위하여 기상모델을 적용할 경우 기온 및 풍속 둥은 지역에 따라 불규칙하게 변화되므로 DLR 추정 및 운용에는 모니터링 위치의 선정 및 측정 개소의 증감 둥 여러 가지 고려해야 할 점들이 존재하게 된다. 측정된 기상요소의 추세들은 DLR 결과에 그대로 반영되므로, 각 기상 요소에 대한 유형을 정확하게 추정할 수 있으면 이 특성을 정량화하여 DLR 계산에 이용할 수 있을 것이다. 본 논문에서는 2001년 1년 동안 대전지방기상청에서 측정된 기상데이터를 사용하여 기상 모델의 각 요소와 DLR추정 결과 사이의 특성을 비교 및 검토하였다.

• Proceedings of the KIPE Conference
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• 2019.07a
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• pp.115-117
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• 2019

In this paper, an intelligent control scheme based on Fuzzy PID controller is proposed for accurate power sharing in DC Microgrid. The proposed Fuzzy PID controller is designed with the aid of a closed loop control based on per unit power of each distributed generator (DG), and accurate power sharing is successfully realized in proportional to each DG's power rating regardless of the line resistance difference or the load change. Thanks to Fuzzy PID controller, the dynamic response becomes faster and the stability of the microgrid system are improved in comparison to conventional PID controller. The superiority of the proposed method is analyzed and verified by simulation in Matlab and Simulink.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.21 no.5
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• pp.112-119
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• 2007

Under normal operating condition, the conductor of overhead transmission line could be always hold it's clearance within the safety margin that is specified in the line design guide of power company. Hence it may be very important to measure/or monitor the dip of the conductor, when building a new line, re-tensioning for an aged conductor, or monitoring dynamic line rating to maximize power capability. In this paper, we suggest a new method to estimate the dip and tension by catenary angle of the conductor. Since most conductors in overhead transmission lines show typical catenary curves, it can be uniquely determined the catenary curve for the conductor from the catenary angle at tower. Based on the catenary curve, the dip or horizontal tension can be easily estimated. Through some simulation and simple experimental results, it is verified that the suggested method can be effectively applied to measure/or monitor conductor dips and tensions in the overhead transmission lines.

• Journal of the Korea Society of Computer and Information
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• v.19 no.2
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• pp.161-171
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• 2014

In this paper the flow dynamics of the flue gas equipment in the desulfurization system was numerically analyzed by simulating the problems for the turbulent and combustion flow from Induced Draft Fan(I.D.Fan) outlet to Booster Up Fan(B.U.Fan) inlet using the commercial CFD software of CFD-ACE+ in CFDRC company for Computational Fluid Dynamic Analysis. The guide vane of this section was examined for the minimum pressure loss and the uniform flow dynamic to B.U.Fan with the proper velocity from I.D,Fan exit to B,U,Fan inlet section at the boiler both the maximum continuous rating and the design base. The guide vanes at I,D.Fan outlet and B.U.Fan inlet were removed and modified by numerical simulation of the CFD analysis. The flue gas at the system had the less pressure loss and the uniform flow dynamics of the flow velocity and flow line by comparing with the old design equipment.

• Journal of the Semiconductor & Display Technology
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• v.20 no.1
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• pp.25-31
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• 2021

The semiconductor and display equipment demands an ultra-fine precision of several nm to several ㎛, and the scale is getting smaller due to the explosive development. The manufacturing process equipment for such products with ultra-fine precision is very sensitive to ultra-small vibrations flowing from the floor, resulting in problems of production defects and yield degradation. The vibration criteria are a standard that regulates the vibration environment of the floor where such precision process equipment will be installed. The BBN vibration criteria defined the allowable vibration velocity level in the frequency domain with a flat and inclined line and presented a rating according to it. However, the actual vibration criteria have appeared with various magnitudes in the frequency domain according to the dynamic characteristics of individual equipment. In this study, the relationship between the relative motion of two major points in the equipment and the vibration magnitude of the floor is presented using the frequency response function of a simple 3-DOF model. It is describing the magnitudes according to the frequency of the floor vibration that guarantees the allowable relative motion and this can be used as the vibration criteria. In order to obtain the vibration criteria experimentally a method of extracting through a modal test was introduced and verified analytically. It provides vulnerable frequency and magnitude to floor vibration in consideration of the dynamic characteristics of individual equipment. And it is possible to know necessary to improve the dynamic characteristics of the equipment, and it can be used to check the vibration compatibility of the place where the equipment will be installed.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.6
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• pp.2739-2746
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• 2011

This paper proposes the method for more effectively calculating X/R which is the ratio of equivalent reactance(X) and resistance(R) of the bulk power system and analyses the characteristic of X/R values by applying the proposed method to the real bulk power systems. X/R is used to determine the rating of the relay in the bulk power systems and its value has been accepted to be big enough to ignore the equivalent resistance of the bulk power systems. However, X/R is calculated as a big number when only the upper transformer and transmission line are considered. The correct approach to calculating X/R needs to consider all the parameters including generators, transformers, lines and loads. This paper calculates X/R of the bulk power systems using dynamic models which have been used to analyse the power system stability. The effectiveness of the proposed method is verified by applying it to the test system and X/R values of the real bulk power systems are analyzed. In addition, the dependence of X/R on the closeness of its calculating locations to the generator is verified by using the marginal loss factor which has been used in the electricity market.