• Journal of Electrical Engineering and Technology
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• v.10 no.5
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• pp.1921-1929
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• 2015

The smart substation is the heart of a transmission system, which is particularly emphasized as the most significant composition of smart grids in China. In order to assess the functionality performance of substation technologies, this paper presents methods used to identify the most promising solutions for smart substation design and to evaluate the technical levels of available technologies. The multi-index optimization model is presented to address the issue of smart substation planning. A mathematical model of the planning decision problem is established with multiple objectives consisting of economic, reliability, and green key indices, and many kinds of concerns including physical and environmentally friendly operations are formulated as a set of constraints. With respect to the assessment of the technical level regarding integration of advanced technologies into a substation, a modified grey whitenization weight function is adopted to structure a novel grey clustering method. The proposed grey clustering approach is used to overcome the difficulty of insufficient quantitative assessment capacity for traditional methods. The evaluation of technical effects provides the classification definition for the development phase and the maturity level of the smart substation. The effectiveness of the proposed approaches in planning decision-making and evaluation of construction efforts is demonstrated with case studies involving the actual smart substation projects of Wenchongkou substation in China Southern Power Grid (CSG) and Mengzi substation in State Grid Corporation of China (SGCC).

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.1079-1081
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• 2007

An L-band Linear Accelerator System for E-beam sterilization is under construction for bio-technology application. The klystron-modulator system as an RF microwave source has an important role as major components to offer the system reliability for long time steady-state operations. A PFN line type pulse generator with a peak power of 71.5-MW, $7\;{\mu}s$, 285 pps is required to drive a high-power klystron. The high power pulse transformer has a function of transferring pulse energy from a pulsed power source to a high power load. The pulse transformer producing a pulse with a peak voltage of 275 kV is required to produce 30-MW peak and 60 kW average RF output power at the frequency of 1.3-GHz. We have designed the high power pulse transformer with 1:13 step-up ratio. The peak and average power capability is 71.5-MW (275 kV, 260 A at load side with $7\;{\mu}s$ pulse width) and 130 kW, respectively. In this paper, we present measurements and its analysis on the design parameters, and an initial test result as well as a design concept on the high-power pulse transformer.

• Proceedings of the KIEE Conference
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• 2004.07c
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• pp.1969-1971
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• 2004

For evaluation of partial discharge performances of electrical power appratus such as Insulator, circuit breaker and transformer and so on, Partial discharge measuring system(ERA) consisted of PD detector including amplifier, coupling capacitor, PD calibrator and voltage divider are used PD measuring system is very important factor which affect the test result and show reliability of test result in test laboratory, In this paper, we describe tracebility and uncertainty of PD measuring system in test laboratory based on IEC 60270.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.430-433
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• 2003

Air-operated valve is one of principal valves that are using to control fluid flow. A period diagnosis for safety of power plants is necessary. But there are many difficulties such as economic loss caused by intone of high cost devices and a matter hard to deal with users. In this study we developed the diagnosis system that usersofpower plants are easy to handle. The diagnosis system is composed of database module, reliability analysis module, design safety nodule and diagnosis test and evaluation module.

• Journal of the Korea Safety Management & Science
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• v.7 no.3
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• pp.97-108
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• 2005

The issue of using information system to ensure competitive power in the market is rising. The outsourcing methods that entrust activities of information system of companies to other expert agencies are increasing as the enterprises make a lot of efforts to put their resources to their heart of business in the process of adopting information system. Recently, ASP (Application Service Provider) as new information technology outsourcing method appears due to development of network technology and spreading of peculating software. ASP defines as a software leasing service which is supplied through networks instead of purchasing application software with high price. For successful implementation of ASP, it is necessary to develop a certification program to ensure safety and reliability of ASP. This paper provides the safe and reliable certification program for ASP. In order to develop it, the critical issues related to service quality and certification of ASP are identified and then evaluation methodology for ASP certification program is proposed. This paper presents application certification as the part of ASP certification program.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.8
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• pp.1305-1310
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• 2008

Traditional maintenance planning is based on a constant maintenance interval for equipment life. In order to consider economic aspect for time based preventive maintenance, preventive maintenance is desirable to be scheduled by RCM(Reliability-Centered Maintenance) evaluation. The main objective of RCM is to reduce the maintenance cost, by focusing on the most important functions of the system and avoiding or removing maintenance actions that are not strictly necessary. So, Markov state model is utilized considering stochastic state in RCM. In this paper, a Markov state model which can be used for scheduling and optimization of maintenance is presented. The deterioration process of system condition is modeled by the stepwise Markov model in detail. Also, because the system is not continuously monitored, the inspection is considered. In case study, simulation results about RCM will be shown using the real historical data of combustion turbine generating unit in Korean power systems.

• Journal of IKEEE
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• v.22 no.3
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• pp.733-737
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• 2018

In this paper, we describe the effects on the power system by adding renewable generator. In order to examine the stability of the system, the system analysis was performed using the PSS/E software. We confirmed whether occur the line overload of system through the load flow analysis and contingency analysis. and confirmed whether exceed of fault current using the fault current analysis. Dynamic stability of the system is analyzed through dynamic simulation. The analysis of the system according to the addition of the renewable generator was carried out according to the power system reliability and electricity quality maintenance standard.

• Proceedings of the KSME Conference
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• 2007.05a
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• pp.250-255
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• 2007

Steam generator tubes play an important role in safety because they constitute one of the primary barriers between the radioactive and non-radioactive sides of the nuclear power plant. For this reason, the integrity of the tubes is essential in minimizing the leakage possibility of radioactive water. The integrity of the tubes is evaluated based on NDE (non-destructive evaluation) inspection results. Especially ECT (eddy current test) method is usually used for detecting the flaws in steam generator tubes. However, detection capacity of the NDE is not perfect and all of the "real flaws" which actually existing in steam generator tunes is not known by NDE results. Therefore reliability of NDE system is one of the essential parts in assessing the integrity of steam generators. In this study POD (probability of detection) of ECT system for ODSCC in steam generator tubes is evaluated using multivariate logistic regression. The cracked tube specimens are made using the withdrawn steam generator tubes. Therefore the cracks are not artificial but real. Using the multivariate logistic regression method, continuous POD surfaces are evaluated from hit (detection) and miss (no detection) binary data obtained from destructive and non-destructive evaluation of the cracked tubes. Length and depth of cracks are considered in multivariate logistic regression and their effects on detection capacity are evaluated.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.17 no.5 s.122
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• pp.448-455
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• 2007

As Decentralized Generation(DG) becomes more reliable and economically feasible, it is expected that a higher application of DG units would be interconnected to the existing grids. This new market penetration of DG technologies is linked to a large number of factors like technologies costs and performances, interconnection issues, safety, market regulations, environmental issues or grid connection constrains. This paper describes the procedures and results for the mechanical, electrical, and environmental tests of MGT on actual grid-connection under Korean regulations. As one of the achievements, the simulation model of MGT was developed, so that it will be able to analyze or propose new distributed generation system using MGT. The field test was conducted in order to respond to a wide variety of needs for noise reduction and utilization and its performance was evaluated in consideration of its operational problems. The MGT is successfully supplying electricity to Korean grids with satisfying various regulations. The suggested strategy and experience for the evaluation of the distributed generation will be used for the introduction of other distributed generation technologies into the grid in the future.

• Journal of the Korean Society for Nondestructive Testing
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• v.34 no.5
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• pp.349-355
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• 2014

Wall thinning defects can occur in the pressure vessels used in a variety of industries. Such defects are related to the flow velocity. Considering the fact that such vessels constitute up to 70 or 80% of the plant structures in a power plant, it is important to measure internal defects as part of a safety evaluation. In this study, optical measurement were applied in a non-destructive evaluation using shearography to ensure the safety and improve the reliability of a power plant through the non-contact, non-destructive evaluation of pressure vessels. In order to verify whether the pressure vessels contained faults, experimental and analytical investigation were conducted to measure any internal defects and out-of-plane deformation from inner temperature changes and pressure changes in the piping of the circulation system. The most important factors in this research were the thickness, width, and length of a defect. An increase in these could confirm an increase in the deformation. Thus, internal defects in a pressure vessel were measured using shearography, which made it possible to ensure the reliability and integrity of the pipe.