• Journal of the Korea Institute of Military Science and Technology
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• v.21 no.5
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• pp.675-683
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• 2018

In this paper, we have proposed a design and verification methods of electrical system and power loads for unmaned aeriel vehicles(UAVs) through electrical load analysis. In order to meet a UAV system requirement and electrical system specifications, we have designed an electrical power system for efficient power supply and distribution and have theoretically analyzed the power loads according to the power consumption and power bus design of UAV. Using electrical system rig, the designed electrical power system has been experimentally verified. Also, we have performed several flight tests to verify the UAV electrical system and power loads. It is concluded that the proposed design and verification method of electrical system for UAV system.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.05a
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• pp.117-120
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• 2002

Electrical power system has very complexity problem that it is plan measurement system to achieve Harmonic State Estimation (HSE). This complexity problem depends on discord of necessary accuracy, certainty of noise that exist in data communication damage and converter, adaptability of network modification and minimum of expense size of system, estimated monitering. Also, quantity of available measurement equipment for harmonic measurement has been limited. Therefore, systematic method that choose measurement location for harmonic state estimation. This paper is that see proposed HSE that use Observability Analysis(OA) for harmonic state estimation of electrical power system. OA depends on measurement number, measurement location and measurement form here, it is analysis method that depend on network form and admittance of the system. OA used achieve harmonic state estimation that it is Applied to New Zealand electrical power system to prove validity of HSE algorithm that propose. This study result about harmonic state estimation of electrical power system displayed very economical and effective method by OA.

• Journal of Electrical Engineering and Technology
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• v.10 no.4
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• pp.1422-1431
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• 2015

The reliability of power system components can be affected by a numbers of factors such as the health level of components, external environment and operation environment of power systems. These factors also affect the electrical parameters of power system components for example the thermal capacity of a transmission element. The relationship of component reliability and power system is, therefore, a complex nonlinear function related to the above-mentioned factors. Traditional approaches for reliability assessment of power systems do not take the influence of these factors into account. The assessment results could not, therefore, reflect the short-term trend of the system reliability performance considering the influence of the key factors and provide the system dispatchers with enough information to make decent operational decisions. This paper discusses some of these important operational issues from the perspective of power system reliability. The discussions include operational reliability of power systems, reliability influence models for main performance parameters of components, time-varying reliability models of components, and a reliability assessment algorithm for power system operations considering the time-varying characteristic of various parameters. The significance of these discussions and applications of the proposed techniques are illustrated by case study results using the IEEE-RTS.

• KEPCO Journal on Electric Power and Energy
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• v.5 no.2
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• pp.67-74
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• 2019

Recently, as the renewable distributed energy resources has increased, the variability within the electrical power distribution system has increased, so that there is a growing concern about the stable electrical power distribution system. For efficient management of future electrical power distribution system, it is necessary to improve the electrical power distribution system operation using new visualization technology. In this paper, we describe the current status of GIS introduction and related technology trends in the field of electrical power distribution, and analyze the necessity of GIS system for electrical power distribution system operation and problems to be solved when introducing GIS technology.

• Proceedings of the KIEE Conference
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• 2006.07a
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• pp.192-193
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• 2006

An AC electrical railroad system has rapidly changing dynamic single-phase load, and at a feeding substation, three-phase electric power is transformed to the paired directional single-phase electric power. There is a great difference in electrical phenomenon between the load of AC electrical railroad system and that of general power system. Electric characteristics of AC electrical railroad's trainload are changed continuously according to the traction, operating characteristic, operating schedule, track slope, etc. Because of the long feeding distance of the dynamic trainload, power quality problems such as voltage drop, voltage imbalance and harmonic distortion may also occur to AC electrical railroad system. These problems affect not only power system stability. but also power quality deterioration in AC electrical railroad system. The dynamic simulation model of AC electrical railroad system presented by PSCAD/EMTDC is modeled in this paper, and then, it is analyzed voltage drop and power quality for AC electrical railroad system both with single-Phase distributed STATCOM(Static Synchronous Compensator) installed at SP(Sectioning Post) and without.

• Journal of Power Electronics
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• v.18 no.2
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• pp.533-546
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• 2018

This study proposes a comprehensive mathematical model that includes coil-system circuit and loss models for power converters in wireless power transfer (WPT) systems. The proposed model helps in understanding the performance of WPT systems in terms of coil-to-coil efficiency, overall efficiency, and output power capacity and facilitates system performance optimization. Three methods to achieve constant output power for variable-load systems are presented based on system performance analysis. An optimal method can be selected for a specific WPT system by comparing the efficiencies of the three methods calculated with the proposed model. A two-coil 1 kW WPT system is built to verify the proposed mathematical model and constant output power control methods. Experimental results show that when the load resistance varies between 5 and $25{\Omega}$, the system output power can be maintained at 1 kW with a maximum error of 6.75% and an average error of 4%. Coil-to-coil and overall efficiencies can be maintained at above 90% and 85%, respectively, with the selected optimal control method.

• Journal of Electrical Engineering and Technology
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• v.8 no.3
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• pp.428-435
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• 2013

Flexible AC Transmission System (FACTS) application study on enhancing the flexibility of AC power system has continued to make progress. A thyristor-controlled series capacitor (TCSC) is a useful FACTS device that can control the power flow by adjusting line impedances and minimize the loss of power flow and voltage drop in a transmission system by adjusting line impedances. Reduced power flow loss leads to increased loadability, low system loss, and improved stability of the power system. This study proposes the optimal location and compensation rate method for TCSCs, by considering both the power system loss and voltage drop of transmission systems. The proposed method applies a multi-objective function consisting of a minimizing function for power flow loss and voltage drop. The effectiveness of the proposed method is demonstrated using IEEE 14- and a 30-bus system.

• Journal of Electrical Engineering and Technology
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• v.1 no.1
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• pp.28-34
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• 2006

Recently, in accordance with the development of IT technology, it is prevalent for power quality monitors to be connected to each other via networks and share their data because such networks provide system-wide insights to customers concerning power quality. Those systems can alarm and display power quality events for the convenience of customers. However, if a power quality event occurs, it is difficult for customers to determine its cause and solution because the systems do not provide appropriate power quality diagnosis functions. The power quality management system presented in this paper has been developed to provide customers with various power quality diagnosis functions so that they can cope well with power quality problems with the right measure in the right place. This paper presents the structure and functions of the developed power quality management system and shows some results of the power diagnosis functions.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.64 no.3
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• pp.111-115
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• 2015

Recently, protection coordination issues can occur due to increased fault current in power system when power system being changed radial power system to grid system such as loop power system, micro grid and smart grid. This paper analyzed Recloser-Fuse coordination in loop power distribution system with Superconducting Fault Current Limiters(SFCLs) when single line ground fault occur in loop power distribution system with SFCLs. We analyzed Recloser-Fuse Coordination in radial power distribution system and changed coordination caused by increased Fault current because of loop system when single line ground fault occur in power distribution system. This paper simulated to improve changed coordination using SFCLs in loop power distribution system. Power distribution system, SFCLs and protective devices are modeled using PSCAD/EMTDC.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.67 no.11
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• pp.1542-1548
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• 2018

When any faults occurred in electrical railway system, operators need to analysis it quickly and accurately. Existing COMTRADE based analysis tools are not enough to analysis faults occurred in electrical railway system. In this paper, it presents some functions to fault analysis for electrical railway system based on fault data formatted COMTRADE. These functions are implemented in PSCAD/EMTDC and it can be shown that analyzed results against actual electrical fault cases which were occurred in the electrical railway power system.