• The Transactions of the Korean Institute of Electrical Engineers P
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• v.63 no.2
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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.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.1
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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.

• Proceedings of the SAREK Conference
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• 2008.06a
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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.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.51 no.6
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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.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.50 no.7
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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.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.3
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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.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.52 no.7
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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.

• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.7 no.1
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• pp.30-36
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• 1993

A simple discontinuous conduction mode(DCM) flyback type active power factor corrector for low power supply resents an effective resistive load to its power input. It is therefore well suited as an inexpensive high power factor rectifier for office equipment. An equivalent circuit model for the Active Power Factor Corrector based on the "Loss Free Resistor" concept is presented. This simple model correctly describes the basic power processing properties of the Active Power Factor Corrector, including input port resistor emulation, output port power some characteristics.teristics.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.6
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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.

• Proceedings of the KIEE Conference
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• 1997.11a
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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.