• KEPCO Journal on Electric Power and Energy
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• 제8권1호
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• pp.21-29
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• 2022

Power generated from renewable energy has continuously increased recently. As the distributed generation begins to interconnect in the distribution system, an accurate generation forecasting has become important in efficient distribution planning. This paper explained method and current state of distributed power generation forecasting models. This paper presented selecting input and output variables for the forecasting model. In addition, this paper analyzed input variables and forecasting models that can use as mid-to long-term distributed power generation forecasting.

• KEPCO Journal on Electric Power and Energy
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• 제7권1호
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• pp.115-123
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• 2021

Through machine learning-based load prediction, it is possible to prevent excessive power generation or unnecessary economic investment by estimating the appropriate amount of facility investment in consideration of the load that will increase in the future or providing basic data for policy establishment to distribute the maximum load. However, in order to secure the reliability of the developed load prediction model in the field, the performance comparison verification between the distribution line load prediction models must be preceded, but a comparative performance verification system between the distribution line load prediction models has not yet been established. As a result, it is not possible to accurately determine the performance excellence of the load prediction model because it is not possible to easily determine the likelihood between the load prediction models. In this paper, we developed a reliability verification system for load prediction models including a method of comparing and verifying the performance reliability between machine learning-based load prediction models that were not previously considered, verification process, and verification result visualization methods. Through the developed load prediction model reliability verification system, the objectivity of the load prediction model performance verification can be improved, and the field application utilization of an excellent load prediction model can be increased.

• KEPCO Journal on Electric Power and Energy
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• 제3권1호
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• pp.41-47
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• 2017

After $SF_6$, which is being used in power equipment as an insulating material, is classified as one of the 6 major greenhouse gases, the maintenance and the refinement of used $SF_6$ started to get attention. In regard to this, KEPCO Research Institute (KEPRI) is developing $SF_6$ recovery and refinement technology starting with establishing a comprehensive $SF_6$ analysis system. With the analysis system, qualitative and quantitative analyses of the purity and the impurities of $SF_6$ before and after recovery, and before and after refinement have been carried out. The analysis system is comprised of GC-DID (Gas Chromatograph -Discharge Ionization Detector) for trace impurities analysis, GC-TCD (Thermal Conductivity Detector) for analyses of $SF_6$ purity and major impurities concentration from several hundred ppm up to percent range, GC-MSD (Mass Selective Detector) for analyses of impurities not included in standard gas, FT-IR (Fourier Transform-Infrared) Spectrometer for analysis of HF and $SO_2$, and moisture analyzer for analysis of moisture below 100 ppm. With this analysis system, complete analysis method of $SF_6$ has been established. This analysis system is being used in the maintenance of power equipment and the development of $SF_6$ recovery and refinement technologies. In this paper, the analysis results of four samples - gas and liquid phase $SF_6$ samples from a $SF_6$ refinement system before and after refinement are presented.

• KIEE International Transactions on Power Engineering
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• 제5A권3호
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• pp.207-213
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• 2005

This paper deals with the development of benchmark systems based on the Korea Electric Power Corporation (KEPCO) system. A novel procedure for constructing a dynamic equivalent system of the KEPCO system is proposed. By using such a system, various scenarios can be simulated and compared with the original system. The results of the simulation show the benefits of the proposed equivalent system and its validity is confirmed by applying it to the KEPCO system.

• 에너지공학
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• 제24권2호
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• pp.154-166
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• 2015

The in-core instrumentation measures core power distribution and coolant temperature in local regions of the core in pressurized water reactors. The installation types are distinguished by the designs of routing paths that exit either through reactor bottom mounted instrument nozzles or through reactor top mounted instrument nozzles. Although each type has unique advantages, it is generally known that top mounted design is more competitive with respect to emphasizing nuclear safety issues and ability to cope with severe accidents. The international nuclear vendors have provided various types of reactors with top mounted design. Nuclear power reactors in Korea, however, only have been designed to be applicable to the use of bottom mounted design, and it has been pointed out that the capabilities of Korean reactors against severe accidents should be further enhanced. The paper deals with technical issues on reactor internal and external design, in-core instrumentation, support assembly, sealing mechanism with nozzles, handling, and analytical issues in order to establish the ways of development.

• KEPCO Journal on Electric Power and Energy
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• 제1권1호
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• pp.9-13
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• 2015

Energy storage systems (ESS) can be used to provide frequency regulation services in a power system to replace traditional frequency regulation power plants. Battery ESS, in particular, can provide "fast-responding frequency regulation," wherein the facility can respond immediately and accurately to the frequency regulation signal sent by the system operator. This paper presents the development and the trial run results of a frequency regulation control system that uses large-scale ESS for use in a large power system. The control system was developed initially for the 4 MW ESS demonstration facility in Jocheon Jeju Island, and was further developed for use in the 28 MW ESS facility at the Seo-Anseong substation and the 24 MW ESS facility at the Shin-Yongin substation to provide frequency regulation services within mainland Korea. The ESS facility in Seo-Anseong substation responds to a sudden drop in frequency via governor-free control, while the ESS facility in Shin-Yongin responds via automatic generator control (AGC).

• KEPCO Journal on Electric Power and Energy
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• 제6권3호
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• pp.245-252
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• 2020

It is very important to evaluate on/off-line stability to operate the power system stably and economically. Until now, we have continuously secured the operation reliability of the power system through the evaluation of transient, voltage and small signal stability. This paper proposes that it is possible to operate in KWAMS by applying the multi-section analysis and subspace methods and verifying the reliability of the algorithms to directly estimate the dominant oscillation mode of the power system from the signal waveform acquired from the phasor measurement units. In addition, this paper shows that the dominant oscillation mode can be detected from real-time measurement data in power systems. Therefore, if we can monitor the state of the power system in real time, it is possible to avoid a large-scale power outage by knowing the possibility of the power system accident in advance.

• KEPCO Journal on Electric Power and Energy
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• 제6권4호
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• pp.419-425
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• 2020

DC distribution system has been evaluated as an excellent one in comparison with existing AC distribution network because it needs fewer power conversion stages and the full capacity of the equipment can be used without consideration for power factor. Recently, research and development on the implementation of DC distribution networks have been progressed globally based on the rapid advancement in power-electronics technology, and the technological developments from the viewpoint of infrastructure are also in progress. However, to configure a distribution network which is a distribution line for DC, more accurate and rapid introduction of analysis technology is needed for the monitoring, control and operation of the system, which ensure the system run flexible and efficiently. However, in case of a bipolar DC distribution network, there are two buses acting as slack buses, so the Jacobian matrix cannot be configured. Without solving this problem, DC distribution network cannot be operated when the network is unbalanced. Therefore, this paper presented a comprehensive method of analysis with consideration of operating elements which are directly connected between neutral electric potential caused by the unbalanced of load in DC distribution network with bipolar structure.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1994년도 하계학술대회 논문집 C
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• pp.1505-1508
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• 1994

Lately in KEPCO, the power plant capacity has increasingly become larger than before and it has become difficult to get R.O.W for T/L. Therefore KEPCO decided to increase its system voltage level from 345kV to 765kV. By doing this, KEPCO would like to expand its transmission capability by less T/L route. In 765kV system, we should consider various kinds of environmental impacts that can be neglected in lower voltage level. These environmental impacts are very important factor in T/L design. That can be changed greatly according to the selected conductor. And also conductor selection has relation with the economy of T/L construction directly. This paper deals with some general factors to be considered and basic principles about the conductor and ground wire selection for 765KV T/L with referring to the experiences of foreign utilities.

• KEPCO Journal on Electric Power and Energy
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• 제1권1호
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• pp.47-54
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• 2015

The most important function in distribution automation system (DAS) is the service restoration. KEPCO's current service restoration provides a very effective restoration service. However, it has been developed without the consideration of unexpected abnormal conditions that may occur while processing the sequence of switching operations. The objective of this paper is to provide practical service restoration schemes under consideration of abnormal conditions. The proposed service restoration schemes have been integrated to a branch office (B/O) in KEPCO. The proposed method strongly supports the conventional service restoration and adds to its value.