• The Transactions of the Korean Institute of Electrical Engineers P
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• v.57 no.1
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• pp.46-55
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• 2008

In this paper, we designed the bay control unit that is based on the microprocessors and integrates with the new technology of electrical, electronic, and mechanical fields. Nowadays the customers have required much more integrated multi-protection relay, monitoring, control devices and power management for better and easier maintenance, performance, electrical system analysis and communication according to new trend of switchboard This bay controller supplies those requirements of customers with easy handling and operation. This bay controller provides a graphic display with rear-lit liquid crystal LCD and push buttons as kinds of HMI(Human Machine Interface). This bay controller provides the parameter setting program, control setting program, various editors and fault recording and analysis program on Windows/95/98/NT/2000/XP for HMI. In addition, this bay controller can be set manually and this manual setting function helps user to interface easily.

• Proceedings of the KIEE Conference
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• 1991.11a
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• pp.47-50
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• 1991

This paper discusses a knowledge-based system being developed by KAIST and KEPCO to assist planning the annual maintenance schedule of power units. To meet users' requirements, we have designed the system with several features: man-machine interaction, catalog system, user-friendliness, the hybrid-system of math-model and knowledge-base. In this paper, we introduce the outline of our system.

• Proceedings of the KIEE Conference
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• 2000.07b
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• pp.952-954
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• 2000

In the cleaning-water treatment process, the flocculation machine is operated by the V.S motor when the coagulation-facility of the coagulation-process is operated. But after the flocculation machine is stopped by an instantaneous power failure, the transient takes place when the coagulation facility is re-started. To improve the transient state, we developed the reinforcement-circuit which had the function of soft-start and adapted to the field. As a result of this study, we reduced the damage of facilities and had the safety in maintaining the quality of water and improved the efficiency in the maintenance and the management.

• 제어로봇시스템학회:학술대회논문집
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• 1994.10a
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• pp.522-526
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• 1994

There are great needs for checking machine operation status precisely in the iron and steel plants. Rotating machines such as pumps, compressors, and motors are the most important objects in the plant maintenance. In this paper back-propagation neural network is utilized in diagnosing rotating machines. Like the finger print or the voice print of human, the abnormal vibrations due to axis misalignment, shaft bending, rotor unbalance, bolt loosening, and faults in gear and bearing have their own spectra. Like the pattern recognition technique, characteristic. feature vectors are obtained from the power spectra of vibration signals. Then we apply the characteristic feature vectors to a back propagation neural net for the weight training and pattern recognition.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.64 no.2
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• pp.62-66
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• 2015

Induction generator is easy to durability and maintenance than the synchronous generator. So, recently Induction generator has been widely applied to small-scale hydroelectric power plant. When the rotor is operating faster than synchronous speed, induction machine can generate electric power. Induction generator has a large inrush currents, such as the starting current of the induction motor. Induction motor has been designed a variety of rotor shape in order to reduce starting current. Since the occurrence of high inrush current cause a voltage drop to the system, it will need to reduce possible. Because the starting current of the squirrel-cage induction motor varies in accordance with the rotor shape, it is necessary to analyze the magnitude of inrush current in order to apply to the generator. In this study, we analyzed the inrush current and the voltage drop caused in accordance with the rotor shape of 1500kw induction generator.

• Journal of Electrical Engineering and Technology
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• v.11 no.1
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• pp.29-37
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• 2016

Fast and accurate fault diagnosis of the position sensor is of great significance to ensure the reliability as well as sensor fault tolerant operation of the Switched Reluctance Wind Generator (SRWG). This paper presents a fault diagnostic scheme for a SRWG based on the residual between the estimated rotor position and the actual output of the position sensor. Extreme Learning Machine (ELM), which could build a nonlinear mapping among flux linkage, current and rotor position, is utilized to design an assembled estimator for the rotor position detection. The data for building the ELM based assembled position estimator is derived from the magnetization curves which are obtained from Finite Element Analysis (FEA) of an SRWG with the structure of 8 stator poles and 6 rotor poles. The effectiveness and accuracy of the proposed fault diagnosis method are verified by simulation at various operating conditions. The results provide a feasible theoretical and technical basis for the effective condition monitoring and predictive maintenance of SRWG.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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• pp.109-109
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• 2010

On-line partial discharge(PD) diagnostic system is the most prominent systems to diagnose insulation condition for the high voltage rotating machines. Partial discharge measuring system(PDMS) series with ceramic coupler(PD detecting sensor) installed hydro generator and high voltage motor have been measured the PD data for many years. The trend of PD magnitude in the on-line PD system increased for some machines. These machines showed a same result in the conventional off-line PD test and PD magnitude decreased after stator winding insulation cleaning. This case study show that PDMS has been proved to be good results by comparing PD magnitude with on-line and off-line PD test and it is important to plan the maintenance project for the hydro generator stator winding because PD value was decreased after insulation cleaning.

• Journal of the Korean Society for Railway
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• v.18 no.4
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• pp.335-343
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• 2015

The role of the turnouts installed on the points of railway branches and intersections is to safely switch the directions of trains. In case of abnormal forces applied to the turnouts due to extreme operating conditions, it is difficult in the current system to conduct accurate diagnosis and measuring. Moreover, the existing measurement devices for turnout switching power are mostly based on foreign technologies, which provide only limited information on the switching power; this information is insufficient for effective monitoring and maintenance. In this paper, through an analysis of the characteristics of the switching and locking function, the problems in turnout power measurements of current electrical point machines in Korea are examined. And based on the results, a new sensor-based method for measuring switching power is proposed.

• Journal of Electrical Engineering and Technology
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• v.13 no.3
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• pp.1166-1172
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• 2018

Degradation due to delamination occurs frequently in the high temperature superconductors (HTS) coil of rotating machines made with 2nd generation (2G) HTS wire, and the authors have observed other similar cases. Since an HTS field coil for a rotating machine is required to have stable current control and maintain a steady state, co-winding techniques for insulation material and epoxy resin for shape retention and heat transfer improvement are applied during coil fabrication. However, the most important limiting factor of this technique is delamination, which is known to be caused by the difference in thermal expansion between the epoxy resin and 2G HTS wire. Therefore, in this study, the experimental results of mixing the ratio of epoxy resin and alumina ($Al_2O3$) filler were applied to the fabrication of small and large test coils to solve the problem of degradation. For the verification of this scheme, eight prototypes of single pancake coils with different shapes were fabricated. They showed good results. The energization and operation maintenance tests of the stacked coils were carried out under liquid neon conditions similar to the operation temperature of an MW-class rotating machine. In conclusion, it was confirmed that the alumina powder mixed with epoxy resin in an appropriate ratio is an effective solution of de-lamination problem of 2G HTS coil.

• Proceedings of the KIEE Conference
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• 2006.10d
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• pp.116-118
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• 2006

Recently more attention is paid to the development of high-speed permanent magnet (PM) synchronous generators driven by gas-turbine, since they are conductive to high efficiency, high power density, small size, low weight, simple mechanical construction, easy maintenance and good reliability. In this paper, the performance analysis of a high-speed PM synchronous generator for military power application considering the min-max operating speed is presented. The output current and power versus DC-link voltage loci can obtained by solving the PM machine's steady-state equations for variable resistive load.