• 전기학회논문지P
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• 제63권2호
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• pp.107-112
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• 2014

To cope with the ever increasing electric power demands in metropolitan areas, a greater underground cable transmission capacity is required. In general, it must be determined whether the temperature in the tunnel maintains the maximum allowable temperature. In order to improve this point, it is used to the loss factor. But, for economic cooling, it is problem to use such loss factor in this country. In this study, based on the load factor in this country, technique for calculating the loss factor has been presents. The suggested method has been tested in a sample section using the computer and the results have shown the usefullness of the suggested method.

• 전기학회논문지
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• 제59권1호
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• pp.40-45
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• 2010

In order to establish the electric distribution system economically and operate efficiently, it becomes important to calculate energy losses of the system more accurately. This importance is not only related for the engineering of utilities' power network but also for the consumers' electric system. The Distribution Loss Factor (DLF) is the fundamental element of calculating the energy losses occurred through the electric system including the electric lines and equipments. Up to now, the DLF is calculated by empirical formulas using the correlation between the DLF itself and Load Factor. However, these methods have some limitations to reflect the various characteristics of the system and the load. In this regard, the novel method proposed here is developed to yield more accurate result of DLF which actively interacting with the characteristics and load patterns of the system. The improvement of accuracy is very significant according to the results of verification presented at the end of this paper.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2008년도 하계학술발표대회 논문집
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• pp.919-924
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• 2008

Power consumption in the building thermal load could be the sum of the building fabric conduction load, building ventilation convection load and other such as radiation loss load. Dynamic Breathing Building (DBB) is the state-of-the-art to improve the wall insulation and indoor air quality(IAQ) performance as making air flow through the wall. This heat recovery type DBB contributes the power consumption saving due to the improved dynamic U-value. KIER twin test cell with static insulation(SI) and dynamic insulation(DI) at KIER was developed to test building power consumption at the real outside conditions. Then, the actual results were compared with the theory to predict the power consumption at the KIER twin test cell and introduced the building new radiation loss factor $\alpha$ to explain the difference between the both the theory and the actual case. As the results, the power consumption at the breathing DI wall building could saved 10.8% at the 2ACH(Air change per hour) compared with conventional insulation. The building radiation loss factor $\alpha$ for this test condition to calibrate the actual test was 0.55 in the test condition.

• 대한전기학회논문지:전력기술부문A
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• 제51권6호
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• pp.284-289
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• 2002

The transmission networks do not consist of perfect conductors and a percentage of the power generated is therefore lost before it reaches the loads. Since this network loss contributes to the cost of suppling power to consumers, it must be considered that the most efficient dispatch and location of generators and loads are to be achieved. In this paper, marginal loss factors are calculated for 12 load levels that represent the impact of marginal network losses on nodal prices at the transmission network connection points at which generators are located. Based on comparison analysis of marginal loss factors on 12 load levels, we found the MLF characteristics in KOREA.

• 대한전기학회논문지:전력기술부문A
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• 제50권7호
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• pp.333-339
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• 2001

The transmission networks are not perfect conductors and a percentage of the power generated is therefore lost before it reaches the loads. This network loss effects to the cost of suppling power to consumers, and must be considered if the most efficient dispatch and location of generators and loads is to be achieved. In this paper, we propose an approximate calculation of marginal loss factors to analyze characteristics of transmission loss of KEPCO power system. These static marginal loss factors are approximately calculated based on the KEPCO's expected summer peak load data of year 2000.

• 전기학회논문지
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• 제66권3호
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• pp.475-485
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• 2017

This paper develops a conversion function and method transforming from daily peak load curve used $LOLE_D$ [days/year] to hourly load curve used $LOLE_H$[hours/year]and describes relationship between $LOLE_D$ [days/year] and $LOLE_H$ [hours/year]. The indices can not only be transformed just arithmetically but also have different characteristics physically because of using their different load curves. The conversion function is formulated as variables of capacity and forced outage rate of generator, hourly load daily load factor and daily peak load yearly load factor, etc. Therefore, the conversion function (${\gamma}={\varphi}$(.)) can not be simple. In this study, therefore, the function is formulated as linear times of separated two functions. One is an exponential formed conversion function of daily load factor. Another is formulated with an exponential typed conversion function of daily peak load yearly load factor. Futhermore, this paper presents algorithm and flow chart for transforming from $LOLE_D$[days/year] to $LOLE_H$[hours/year]. The proposed conversion function is applied to sample system and actual KPS(Korea Power System) in 2015. The exponent coefficients of the conversion functions are assessed using proposed method. Finally, assessment errors using conversion function for case studies of sample system and actual system are evaluated to certify the firstly proposed method.

• 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.

• 한국조명전기설비학회지:조명전기설비
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• 제7권1호
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• pp.30-36
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• 1993

본 연구는 정류기의 입력전류에 포함되어 있는 고조파성분을 제거하고 입력역률을 개선하기 위해 무손실 저항(Loss Free Resistor) 개념에 기본을 둔, PC, 가전기기 및 형광등용 전자안정기등과 같은 저전력 전원설비에 적합한 불연속 도통모드(DCM) 플라이백 방식의 능동역률 보정기의 등가회로모델 및 설계법을 제시하였다. 이 개념에 의하여 능동역률 보정기의 등가입력저항, 출력전력원 특성을 정확하게 나타낼 수 있었으며 또 설계방정식을 유도하여 능동역률 보정기를 설계 시험한 결과, 적은 부품으로 정류기의 입력교류 전류에 포함되어 있는 고주파를 제거하였고 따라서 0.98의 고입력역률의 정류를 할 수 있었다.

• 전기학회논문지
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• 제57권6호
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• pp.924-931
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• 2008

This paper presents a buswise transmission loss allocation algorithm utilizing the transaction strategy. We prove that whatever calculated by any transaction strategy, the total of the allocated transmission losses of each bus, including no-load loss allocation, almost equals the total loss of AC power flow algorithm and the loss is perfectly slackbus-independent. In this paper, the allocated transmission losses of each bus is calculated by the method of integrating loss sensitivities using by the load level parameter ${\lambda}$. The performance of the proposed algorithm is evaluated by the case studies carried out on the WSCC 9-bus and IEEE 14-bus systems.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1997년도 추계학술대회 논문집 학회본부
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• pp.541-543
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• 1997

In this paper, a proposed resonant PWM switching technique makes the boost AC/DC converter to high input power factor and less switching loss. Also, the switching control scheme is used which minimize harmonic components employing novel PWM technique. In addition, an employment of resonant circuit for switching makes zero current switching(ZCS) and zero voltage switching(ZVS) for control switches without switching losses. The result shows that high power factor is still for varying load and switching loss is very low.