• Journal of Electrical Engineering and Technology
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• 제9권1호
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• pp.45-51
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• 2014

Distribution system is a critical link between customer and utility. The control of power loss is the main factor which decides the performance of the distribution system. There are two methods such as (i) distribution system reconfiguration and (ii) inclusion of capacitor banks, used for controlling the real power loss. Considering the improvement in voltage profile with the power loss reduction, later method produces better performance than former method. This paper presents an advanced evolutionary algorithm for capacitor inclusion for loss reduction. The conventional sensitivity analysis is used to find the optimal location for the capacitors. In order to achieve a better approximation for the current candidate solution, Opposition based Differential Evolution (ODE) is introduced. The effectiveness of the proposed technique is validated through 10, 33, 34 and85-bus radial distribution systems.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• 제3B권2호
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• pp.103-110
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• 2003

With significant development of power electronics technology, the proliferation of nonlinear loads such as static power converters has deteriorated power quality in power transmission and distribution systems. Notably, voltage harmonics resulting from current harmonics produced by the nonlinear loads have become a serious problem in many countries. Many photovoltaic power generation systems installed in building systems have harmonics that are the worst object for distribution systems as a utility interactive system, and it tends to spread out continuously. Proposed and implemented in this paper is a multi-function inverter control strategy that allows a shunt active filter function to the power inverter of the photovoltaic power generation system established on a building system. The effectiveness of the proposed system is demonstrated through the simulation of a hypothetical power system using PSCAD/EMTDC.

• 전기학회논문지
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• 제61권4호
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• pp.513-521
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• 2012

With the advent of smart grid, distribution network charges have been one of keystones of ongoing deregulation and privatization in power industries. This paper proposes a new charging methodology to allocate the existing distribution network cost with an aim of reflecting the true cost and benefit of network customers, especially of distribution generator (DG). The proposed charging methodology separates distribution network costs due to the respective real and reactive power flows. The costs are then allocated to network users according to each charge for the actual line capacity used and available capacity. This distribution network charging model is able to provide the economic signals to reward network users who are contributing to better power factors, while penalizing customers who worsen power factors. The proposed method is shown on IEEE 37 bus system for distribution network, and then the results are validated through the comparison with the MW-Miles and MVA-Miles methods. The charges derived from the proposed method can provide appropriate incentives/penalties to network customers to behave in a manner leading to a better network condition.

• 한국초전도ㆍ저온공학회논문지
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• 제12권1호
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• pp.22-27
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• 2010

This paper analyzed bus voltage sag caused by recloser-fuse coordination in a power distribution system with SFCL. Generally, the recloser is installed to upstream of fuse to clear against both permanent and temporary faults appropriately, when the fault happened and to block expansion of the fault area. Furthermore, when the fault occurred, bus voltage sag is caused by increased fault currents. However, in a power distribution system with SFCL, the fault current could be decreased by the effect of the impedance value of the SFCL and place to install one as long as it could improve bus voltage sag. Therefore, to analyze the effect of the improvement of bus voltage sag caused by recloser-fuse coordination in a power distribution system with SFCL, we used PSCAD/EMTDC about a permanent fault at the place behind the fuse.

• Journal of Electrical Engineering and Technology
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• 제8권3호
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• pp.453-463
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• 2013

The probabilistic nature of renewable energy, especially wind energy, increases the needs for new forms of planning and operating with electrical power. This paper presents a novel approach for determining the short-term generation schedule for optimal operations of wind energy-integrated power systems. The proposed probabilistic security-constrained optimal power flow (P-SCOPF) considers dispatch, network, and security constraints in pre- and post-contingency states. The method considers two sources of uncertainty: power demand and wind speed. The power demand is assumed to follow a normal distribution, while the correlated wind speed is modeled by the Weibull distribution. A Monte Carlo simulation is used to choose input variables of power demand and wind speed from their probability distribution functions. Then, P-SCOPF can be applied to the input variables. This approach was tested on a modified IEEE 30-bus system with two wind farms. The results show that the proposed approach provides information on power system economics, security, and environmental parameters to enable better decision-making by system operators.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 D
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• pp.1569-1571
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• 1999

In this work, we have performed the application experiment for real distribution line to diagnose the underground power cables using DC voltage decay measurement system. We have also performed the Isothermal Relaxation Current test for the same distribution line using KDA-l. We could confirmed possibility of grading the insulation aging state of underground power cables. Therefore, we conclude that it is possible to apply DC voltage decay method to the real distribution line.

• Journal of Electrical Engineering and Technology
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• 제3권4호
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• pp.593-598
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• 2008

The power distribution is proposed to determine the target operating points of the system components as the basis for maximal the efficiency of the overall system for a power split dual electric machine hybrid electric bus. The coordinated control is constructed on the basis of the power distribution. The basic coordinated control is implemented to satisfy the driver's power demand, in which both the dynamic characteristics of the engine and the dual electric machine are explicitly taken into account. Moreover, the improved coordinated control is suggested to suppress engine dynamic operation and rich fuel injection.

• 대한전기학회논문지:전력기술부문A
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• 제52권9호
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• pp.506-512
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• 2003

In this paper, a communication module between Relay agents in a multi-agent system based power distribution network protection system is realized using DNP3.0(Distributed Network Protocol), which is the standard communication protocol of distribution automation system in KEPCO. The key words for agent communication in the multi-agent based protection system are defined and represented by use of DNP application function code. The communication module developed based on the proposed communication scheme is tested by use of the Communication Test Harness, a test tool for DNP protocol, then used to the multi-agent system based power distribution net work protection system.

• KEPCO Journal on Electric Power and Energy
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• 제8권1호
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• pp.15-19
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• 2022

The radial distribution systems (RDS) commonly used around the world has the following disadvantages. First, when the DL is operated on a radial system, the line utilization rate is usually kept low. Second, if a fault occurs in the radial DL, a power outage of 3 to 5 minutes is occurring depending on the operator's proficiency and fault situation until the fault section is separated and the normal section is replaced. To solve this problem, Various methods have been proposed at domestic and foreign to solve this problem, and in Korea, research is underway on the advanced system of operating multiple linked DL always. A system that is electrically linked always, and that is built to enable high-speed communication during the protection coordination is named networked distribution system (NDS). Because the load shares the DL, the line utilization rate can be improved, and even if the line faults, the normal section does not need to be cut off, so the normal section does not experience a power outage. However, since it is impossible to predict in which direction the fault current will flow when a failure occurs in the NDS, a communication-based protection coordination is used, but there is no backup protection coordination method in case of communication failure. Therefore, in this paper, we propose a protective cooperation method to apply as a backup method when communication fails in NDS. The new method is to change TCC by location of CB using voltage drop in case of fault.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 추계학술대회 논문집 학회본부 B
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• pp.640-642
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• 1999

Recent work within the DNP work group has resulted in the proposal, DNP 3.0, as the informative interface for distribution automation systems. This proposed standard embodies the generic principles developed and used within generic protocol. This paper describes a compliance test procedure specifically for Distribution Automation System, practical experience.