• Proceedings of the KIEE Conference
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• 1999.07c
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• pp.1117-1119
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• 1999

This paper presents a new approach for the optimal routing problem of distribution system planning using the well known Hopfield Neural Network(HNN) method. The optimal routing problem(ORP) in distribution system planning(DSP) is generally formulated as combinational mixed integer problem with various equality and inequality constraints. For the exceeding nonlinear characteristics of the ORP most of the conventional mathematical methods often lead to a local minimum. In this paper, a new approach was made using the HNN method for the ORP to overcome those disadvantages. And for this approach, a appropriately designed energy function suited for the ORP was proposed. The proposed algorithm has been evaluated through the sample distribution planning problem and the simulation results are presented.

• Journal of Electrical Engineering and Technology
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• v.11 no.3
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• pp.575-584
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• 2016

Considering the randomness and uncertainty of wind power, a reliability model of WTGs is established based on the combination of the Weibull distribution and the Markov chain. To analyze the failure mode quickly, we use the switch-section partitioning method. After defining the first-level load zone node, we can obtain the supply power sets of the first-level load zone nodes with each WTG. Based on the supply sets, we propose the dynamic division strategy of island operation. By adopting the fault analysis method with the attributes defined in the switch-section, we evaluate the reliability of the distribution network with WTGs using a sequential Monte Carlo simulation method. Finally, using the IEEE RBTS Bus6 test system, we demonstrate the efficacy of the proposed model and method by comparing different schemes to access the WTGs.

• KIEE International Transactions on Power Engineering
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• v.5A no.2
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• pp.125-131
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• 2005

Service restoration is one of the most important missions in distribution system operation. This paper proposes a multi-agent system approach to distribution system restoration. Every relay is developed as an agent by adding its own intelligent, self-tuning and communication ability. The relay agent independently calculates and corrects its restoration index through communication with neighboring agents and its own intelligence. The proposed algorithm is applied to a simple network to demonstrate its soundness and effectiveness.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.49 no.11
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• pp.566-574
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• 2000

This paper propose a heuristic algorithm based on the Branch-Exchange (BE) method to solve Optimal feeder Routing(OFR) problem for the distribution system planning. The cost function of the OFR problem is consisted of the investment cost representing the feeder installation and the system operation cost representing the system power loss. We propose a properly designed heuristic strategy, which can handle the horizon-year expansion planning problem of power distribution network. We also used the loop selection method which can define the maximum loss reduction in the network to reduce calculation time, and proposed a new index of power loss which is designed to estimate the power loss reduction in the BE. The proposed index, can be considered with both sides, the low voltage side and voltage side branch connected with tie one. The performances of the proposed algorithms and loss index were shown with 32, 69 example bus system.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.50 no.5
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• pp.241-247
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• 2001

Network reconfiguration in distribution systems is realized by changing the status of sectionalizing switches, and is usually done for loss reduction of load balancing in the system. This paper presents an effective heuristic based switching scheme to solve the distribution feeder loss reduction problem. The proposed algorithm consists of two parts. One is to set up a decision tree to represent the various switching operations available. Another is to apply a proposed technique called cyclic best first search. the proposed algorithm identify the most effective the set of switch status configuration of distribution system for loss reduction. To demonstrate the validity of the proposed algorithm, numerical calculations are carried out the 32, 69 bus system models.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.17 no.3
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• pp.87-94
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• 2003

When faults occur in a distribution network, blackout loads must be restored as fast as possible to minimize interruption of electric service. This paper presents an expert system to restore distribution networks. The system is designed to minimize switching operations in a heuristic sense by using heuristic rules. The restoration process is converted to the feasible path finding problem in the state space of expert system by application of general topological knowledge base. Multiple load transfer algorithm is proposed to deal with complex situations.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.50 no.4
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• pp.188-196
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• 2001

This paper presents and efficient algorithm for the loss minimization by automatic sectionalizing switch operation in distribution systems. Ant colony algorithm is multi-agent system in which the behaviour of each single agent, called artificial ant, is inspired by the behaviour of real ants. Ant colony algorithm is suitable for combinatiorial optimization problem as network reconfiguration because it use the long term memory, called pheromone, and heuristic information with the property of the problem. The proposed methodology with some adoptions have been applied to improve the computation time and convergence property. Numerical examples demonstrate the validity and effectiveness of the proposed methodology using a KEPCO's distribution system.

• Journal of Electrical Engineering and Technology
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• v.8 no.4
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• pp.729-736
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• 2013

Power grids are large complicated networks in use around. An absolute phase value for a particular unknown-phase line at a local site should be identified for the operation and management of a 3-phase distribution network. The phase shift for a specific point in the line, as compared with a phase reference point at a substation, must be within a range of ${\pm}60^{\circ}$ for correct identification. However, the phase shift at a particular point can fluctuate depending on the line constants, transformer wiring method, line length, and line amperage, etc. Conducted in this study is a theoretical formulation for the determination of phase at a specific point in the line, Simulink modeling, and analysis for a distribution network. In particular, through evaluating the effects of unbalanced current loads, the limitations of the present phase identification methods are described.

• Journal of information and communication convergence engineering
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• v.3 no.2
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• pp.90-92
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• 2005

As the result of the study shows, Round Robin Algorithm allows servers to ensure definite traffic distribution, unless incoming data loads differ much. Although error levels are high in some cases, they were eventually alleviated by repeated tests for a long period of time. The study uses two software packages (Packet Capture and Round Robin Test Package) to check packet volume from Virtual Network Structure (data generator, virtual server, Server 1, 2, 3), and finds out traffic distribution toward Server 1, 2, and 3. The functions of implemented Round Robin Load Balancing Monitoring System include round robin testing, system monitoring, and graphical indication of data transmission and packet volume.

• Proceedings of the KIEE Conference
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• 1998.11a
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• pp.329-331
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• 1998

This paper presents a modified Learning Vector Quantization rule to control shunt capacitor banks and feeder voltage regulators in electric distribution systems with Kohonen Neural Network(KNN). The objective of the KNN is on-line decision of the optimal state of shunt capacitor banks and feeder voltage regulators which minimize $I^{2}R$ losses of the distribution system while maintaining all the bus voltages within the limits. The KNN is tested on a distribution system with 30 buses, 5 on-off switchable capacitor banks and a nine tap line voltage regulator.