• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 G
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• pp.3051-3053
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• 1999

In recent years, it becomes a worldwide trend that the power utilities focus their attention to Demand Side Management. Increasing Electric power consumption, they adopt a direct load management to accomplish low cost and stability of electric supply. Following this trend, KEPCO is researching a Direct Load Control System for Air Conditioner. This Paper presents the development results of the Direct Load Control System to Control electric power consumption of Conditioner in summer period this year.

• Journal of Power Electronics
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• 제16권1호
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• pp.102-110
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• 2016

Contactless power transfer technology is gaining increasing attention in city transportation applications because of its high mobility and flexibility in charging and its commensurate power level with conductive power transfer method. In this study, an inductively coupled contactless charging system for a 48 V light electric vehicle is proposed. Although this study does not focus on system efficiency, the generic problems in an inductively coupled contactless power transfer system without ferromagnetic structure are discussed. An active load matching method is also proposed to control the power transfer on the receiving side through a load matching converter. Small signal modeling and linear control technology are applied to the load matching converter for port voltage regulation, which effectively controls the power flow into the load. A prototype is built, and experiments are conducted to reveal the intrinsic characteristics of a series-series resonant inductive power charger in terms of frequency, air gap length, power flow control, coil misalignment, and efficiency issues.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 D
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• pp.2825-2827
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• 2000

In electric power industry. load balance has been one of the most fundamental and important management goals. Therefore. the strategy to achieve high quality load management now includes load balance besides the stabilization of electricity supply and quality management of electricity. Amongst many techniques of load management. direct load management has been actively studied and utilized to increase power facility and peak load suppression. Higher peak load situation is appeared during summer than during winter in Korea. and approximately 20% of the peak load is due to the load for air-conditioning. To cope with this peak load problem during summer KEPCO is performing a research project to develop a system to remotely control air-conditioning load using wireless communication. Currently, applicable facilities are limited to small-scale air-conditioning facility that has less than 2KW power capacity. This paper described the 1st year of efforts made in the study.

• Journal of Electrical Engineering and Technology
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• 제13권4호
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• pp.1419-1424
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• 2018

Very short-term electric load forecasting is essential for real-time power system operation. In this paper, a very short-term electric load forecasting technique applying the Kalman filter algorithm is proposed. In order to apply the Kalman filter algorithm to electric load forecasting, an electrical load forecasting algorithm is defined as an observation model and a state space model in a time domain. In addition, in order to precisely reflect the noise characteristics of the Kalman filter algorithm, the optimal error covariance matrixes Q and R are selected from several experiments. The proposed algorithm is expected to contribute to stable real-time power system operation by providing a precise electric load forecasting result in the next six hours.

• 대한원격탐사학회지
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• 제23권5호
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• pp.393-400
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• 2007

We present in this paper a novel power load prediction method using temporal pattern mining from AMR(Automatic Meter Reading) data. Since the power load patterns have time-varying characteristic and very different patterns according to the hour, time, day and week and so on, it gives rise to the uninformative results if only traditional data mining is used. Also, research on data mining for analyzing electric load patterns focused on cluster analysis and classification methods. However despite the usefulness of rules that include temporal dimension and the fact that the AMR data has temporal attribute, the above methods were limited in static pattern extraction and did not consider temporal attributes. Therefore, we propose a new classification method for predicting power load patterns. The main tasks include clustering method and temporal classification method. Cluster analysis is used to create load pattern classes and the representative load profiles for each class. Next, the classification method uses representative load profiles to build a classifier able to assign different load patterns to the existing classes. The proposed classification method is the Calendar-based temporal mining and it discovers electric load patterns in multiple time granularities. Lastly, we show that the proposed method used AMR data and discovered more interest patterns.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 제37회 하계학술대회 논문집 A
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• pp.264-265
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• 2006

This paper presents direct load control algorithm based locational and electric load characteristics. Direct load control is defined that demand-side management program activities that can interrupt consumer load at the time of annual peak load by direct control of the utility system operator by interruption power supply to individual appliances or equipment on consumer premises. Korean power system is divided into 14-areas considering branches operating in KEPCO, and electric loads are classified into 19 load groups considering interruption costs in this paper. The purpose of proposed method is to decrease social losses by controlling electric loads mainly whose interruption costs are low. It is expected that the proposed algorithm can be used as the countermeasure for the emergency state of the electric power dispatch in a operation point of view.

• 대한전기학회논문지:전력기술부문A
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• 제52권4호
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• pp.213-218
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• 2003

In front of the opening of electric distribution market in 2004, it is indispensable to have a proper estimation of power quality index and rower quality cost calculation mechanism which are indispensable to stabilize highly industrialized society and to vitalize the Investment lot electric power system. However, there were not enough measures to reflect the voltage characteristics such as voltage sags and Interruptions which make electric load in unstable operation. This paper suggests power quality index and power quality cost which translate various kinds of voltage records into bus load drop index(BLDI) and bus power quality cost(BPQC) based on aggregated load CBEMA curve. A sample calculation result shows that this method can produces the acceptable power Quality index and costs for utilities and customers requirements.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 제37회 하계학술대회 논문집 A
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• pp.218-219
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• 2006

This paper is about modeling on 1500V DC electric railroad system. Electric railroad systems have peculiar characteristics against other electric system. The characteristics arc that the railroad systems have electric vehicle loads which are power-varying and location-varying with time. Because of this load characteristic, the electric railroad system modeling which reflects its own characteristics on EMTDC simulation could not be achieved. However, to reflect load characteristic on EMTDC, this paper suggests electric railroad system modeling by using TPS (Train Performance Simulator) that was developed in Korea Railroad Research Institute. A TPS program has various kinds of input data, such as operation condition, vehicle condition, and power system condition. By these data, TPS calculates mechanical power consumption and location, especially it decide electric power consumption on the basis of the fact that consumed electric and mechanical power are equal. Moreover, on this paper, movement of vehicle is reflected on EMTDC simulation as variation of feeder impedance. Also, an electric vehicle load is modeled as time-varying constant power load model.

• KEPCO Journal on Electric Power and Energy
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• 제2권3호
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• pp.403-407
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• 2016

In general, drum-type boilers are designed for base load duty and applied under constant pressure operation mode. Recently, however conditions often occur that even drum-type boilers have to operate at partial load conditions. A feasibility study on adopting the sliding pressure operation for drum-type boiler was conducted, and corresponding performance changes and effects on the equipment were analyzed by utilizing a process simulation model. As a result, the conclusion was reached that drum type boilers are able to adopt the sliding pressure operation and can improve of net efficiency at part load operation in spite of the Rankine cycle efficiency reduction due to the decreases in main steam pressure. Because of thank to improvement of high pressure turbine stage-1 internal efficiency and power savings of boiler feed water pump. The sliding pressure operation is advantageous in terms of stress level relief for boiler tube as well as maintaining the rating steam temperature at part load condition. However, cautions are required because the drum boilers have poor dynamic response characteristics which may get worse during the sliding pressure operation.

• Journal of Advanced Marine Engineering and Technology
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• 제24권3호
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• pp.106-112
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• 2000

Since the oil crisis, we have been concerned about the energy saving techniques of electric generating systems. As a part of the effort to save energy, automatic electric load sharing device was developed. Usually, ship's electric generating system consists of two or three sets of generator. And, electric generating system is operated as single or parallel operation mode according to the demanded electric power. Therefore, it is important to investigate generators operating mode for the supply of required electric power in the ship in order to decrease the operating cost. So, this paper suggests the method to solve the optimal electric load distribution problem by dynamic programming. And, this thesis indicates that the proposed method is superior to the lagrange multiplier's method in obtaining optimal load distribution solution in the ship's electric generating system.