• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.18 no.1
• /
• pp.98-104
• /
• 2004

This paper represents the fast and efficient load transfer guide for fault or outage restoration in distribution system. For restoration guide, system trace is performed to reverse direction(source side) from tie breaker in tree-structured distribution network. Search space and breaker's combinational number for restoration guide are greatly reduced. It is proposed the load transfer method including first stage restoration(single load transfer, double load transfer, triple load transfer), second stage restoration(transferring load to neighboring feeder in order to expand the capacity margin) and load cutoff guide. The proposed method can be easily applied to primary customer restoration, multi-fault recovery and distribution automation system.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.18 no.5
• /
• pp.105-111
• /
• 2004

This paper shows that active and reactive power load have significant positive relationship and there exist two types of relationship between them using Test Statistics. In investigating the cross plots at every hour, we found out that from 0 to 8 hours, there relationships are linear, while from 9 to 23 hours, they are two piece-wise linear. Also, reactive power loads was estimated and forecasted using active power load as the explanary variable with OLS (Ordinary Least Squares) regression methods. MAPE (Mean Absolute Percentage Error) for each model is calculated for one-hour ahead forecasting.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.17 no.6
• /
• pp.23-30
• /
• 2003

This paper analyzes the characteristic of utility connection type solar power generation system which it is available to connect the utility. And the operation characteristic of this system is compared and analyzed when it is operated in the real system. The constructional and operational problem were obtained by that result. Overcoming that defect is that finding the proper place to be well operated and to find the best place for getting the sunshine data. This method could increase the efficiency of the generation system. And more, current OS in operating system and monitoring management couldn't solve the problem so that improving OS and constructing data backup system should be implemented, This paper proposes the plan to solve that defect in the real system.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.21 no.7
• /
• pp.29-36
• /
• 2007

According to the using of electric power source such as solar cell, fuel cell and wind energy, consumer is supplied from distributed generator and electric power company. Therefore, it is required that the real-time measurement and control instrument for those distributed generator. In this paper, describes the development of measuring equipment for the power system with distributed generator. The equipment has real-time measure function and communication with PC via USB port, which is used for various purposes such as investigation of transient state, and is compared with measurement instrument to verify the reliability.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.17 no.5
• /
• pp.94-102
• /
• 2003

This paper presents active management of feeder automation systems using active database. DAS(Distribution Automation System) has been managed for feeder automation in passive manner. Therefore, feeder automation system has to be managed by operator when feeder overloadings is detected. It may be possible for propagating the feeder overloadings area by operator's mistake. To overcome this defect, the author proposed the feeder automation technique with active manner to obtain feasible feeder reconfiguration. Active database can manage feeder automation system by data driven monitoring of events and by corresponding actions without operator's intervening. To manage feeder automation system with active manner, production rule, active rule manager are designed. And active database system architecture for feeder automation system is proposed. Test results on the KEPCO's 108 bus distribution system show that the performance is efficient and robust.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.20 no.3
• /
• pp.69-77
• /
• 2006

This paper presents the service restoration in electric power distribution systems. The aim of the service restoration is to control an emergency taken place in distribution systems and to restore out-of service areas as soon as possible when a fault occurs in distribution systems. For this reason, new service restoration strategies in multi-outage area are suggested in this paper. The suggested algorithm consist of two schemes. One is an individual restoration scheme, the other is an integrated restoration scheme. The former determines a restoration order of outage areas based on a restoration index. Unless the former scheme can generate a feasible restoration plan, the latter one will try to find out a new configuration without an overloaded section through tie exchange method.

• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.9 no.2
• /
• pp.35-41
• /
• 1995

This paper proposes an adaptive methodology for setting of the underfrequency relays that is based on the initial rate of change of the frequency decline to protect for excess frequency decline of power system under large generator outage. The strategy of the load shedding is as follows : Let the load shedding of the first step occur when the frequency reaches 59.5 (Hz), and the load shedding power of this first and second step be one half of the total "Static Load Shed" value for any given disturbance size based on the initial rate of change of the frequency. As a results, it is verified that the use of the proposed method is more efficient than the conventional method in the characteristic of the frequency recovery. recovery.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.18 no.2
• /
• pp.142-149
• /
• 2004

This paper presents a neural network controller of a grid-connected wind energy conversion system for extracting maximum power from wind and a power controller to transfer the maximum power extracted into a utility grid. It discusses the modeling and simulation of the wind energy conversion system with the controllers, which consists of an induction generator, a transformer, a link of a rectifier, and an inverter. The paper describes tile drive train model, induction generator model and grid-interface model for dynamics analysis. Maximum power extraction is achieved by controlling the pitch angle of the rotor blades by a neural network controller. Pitch control method is mechanically complicated, but the control performance is better than that of the stall regulation. The simulation results performed on MATLAB show the variation of the generator torque, the generator rotor speed, the pitch angle, and real/reactive power injected into the grid, etc. Based on the simulation results, the effectiveness of the proposed controllers is verified.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.14 no.5
• /
• pp.36-42
• /
• 2000

The increasing application of power electronic equipment 'especially (ASDs: adjustable speed drives)] on distribution systems has led to a growing concern for harmonic distortion and the resulting impacts on system equipment and operations. Therefore, harmonic studies have become an important aspect of power system analysis and design in recently years. Computer simulations which is related harmonic are used to quantify the distortion in voltage waveforms in a power system. Many digital computer programs are available for harmonic analysis. In frequency spectrum analysis, Simulation using SuperHarm program is superior to simulation using others. Therefore, Computer simulation using SuperHarm program is one of the effective ways to assess the harmonic effects of ASDs. The purpose of this study is to calculate the quantity of harmonic voltage by varying the ASD side load and to design the optimal harmonic filter for the elimination of harmonics.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.22 no.1
• /
• pp.141-148
• /
• 2008

This paper presents experimental results on the safety of persons and protection of low-voltage equipments of the sub-station due to a single-phase ground fault in 22.9 kV-Y distribution system. In order to evaluate the hazard voltages and the stress voltage of the low-voltage(LV) equipment due to faults between high-voltage systems and earth based on the newly prescribed KS C IEC 60364 standard series, the verification tests in a 22.9[kV] neutral multiple grounding system were carried out. From the experimental results, we introduce serious problems causing some discomfort when applying KS C IEC 60364 standard series to the existing domestic distribution system and the effective protective measures against temporary overvoltages due to a ground fault in the common grounding which is combined the 22.9 kV-Y grounding and the customer's installation grounding are proposed. As a consequence, it was found that the equipotential bonding is an important prerequisite for the effectiveness of the protective measures for the safety of persons and LV equipment in the combined 22.9 kV-Y and low-voltage grounding system.