• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.54 no.1
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• pp.73-80
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• 2018

Intermittent duty of emergency generator has problems emitting large quantities of PM and NOx in exhaust gas. The aim of this study is to propose DPF system which can be applied to medium-large emergency generators. The system is composed of soot dust collector, silencer and filter trap, which is designed to reduce PM emissions at the emergency generator start-up. The pneumatic system controls a flow direction of exhaust gas to pass through the soot collector and filter trap until the engine reaches complete combustion condition. An experiment is performed to measure PM content and concentration to analyze the performance and characteristics of the proposed system.

• Journal of Electrical Engineering and Technology
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• v.4 no.3
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• pp.301-309
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• 2009

A simple and efficient Lambda logic (${\lambda}-logic$) based algorithm is proposed for the solution of the generator constrained economic dispatch problem when the generating units having prohibited zones. The proposed method solves the economic dispatch (ED) problem that takes into account ramprate limits, transmission losses and prohibited operating zones in the power system operation. The proposed method uses a simple heuristic rule based on average power of prohibited operating zones which produces the feasibility of solution for the restricted operating units. The effectiveness of the algorithm is tested on five different test systems and the performance compared with other relevant methods reported in the literature. In all the cases, the proposed algorithm performs better than the previous existing algorithms with a less computational burden.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.63 no.3
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• pp.149-156
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• 2014

Generator of hydroelectric generating unit is to be protected by the digital protection IED. Now, any IED of large capacity for hydro power plant was not developed by domestic technology. This is because it is required for the generator of the high reliability technology and considered as due to the sale of the market of IED device is small. However, the protection IED must be develop by domestic technology to meet the advanced needs of the construction and replacement of electrical equipment in accordance with the new power plant development. In this paper, a digital algorithms for protection IED of large size of hydroelectric generating unit were designed. The algorithms consist of the stator protection, anti-motoring, overexcitation and loss of excitation. The performance of the algorithms were evaluated by using the simulation data collected from the PSCAD/EMTDC software. From test results, it can be seen that the developed algorithms were not maloperation.

• Proceedings of the KIEE Conference
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• 2006.07a
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• pp.527-528
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• 2006

This paper presents a coordination algorithm for the protection of large wind farm of which consists loop connection system that is able to disconnect fault section from wind farm. The proposed coordination algorithm can distinguish between inner and outer fault of wind farm. by using changing of ratio generator output current over loop branch current connected to each generator. A series of PSCAD/EMTDC simulation results have shown effectiveness of the proposed algorithm.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.33B no.9
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• pp.107-116
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• 1996

In the stochastic structure for doing exact calculationk, an input number must be changed to a pulse stream. Because the performance of random number generator (RNG) is controlled by its initial condition, we suggested newly modified cellular automata (MCA) which is uses a counter for boundary condition. We compared newly suggested MCA RNG to previously reported RNGs using the AND gate passing outputs which have the same meaning of multiplication in the stochastic calculation. In order to use stochastic we studied about the method, one large RNG can generate many small random numbers. In this method, RNG must have large drive capabilities for many input comparator. So we studied about drive capabilities using BiCMOS circuit and CMOS circit by SPICE.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.53 no.3
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• pp.103-109
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• 2004

This paper has presented, taking an example of a gas separation plant, dynamic analysis on frequency decline caused by the over-loading at the generator and the knee point causing voltage instability due to reactive power required by re-acceleration of large induction motors, resulting in phenomena of failure in the conventional frequency load shedding. In order to resolve the voltage instability problem, a design of load shedding system employing under-voltage relays has been proposed to the industrial power system containing large induction motors in addition to the conventional load shedding employing frequency relays. For the purpose of dynamic analysis, models of gas turbine and governor, synchronous generator, brushless exciter, and induction motor are introduced.

• The Bulletin of The Korean Astronomical Society
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• v.44 no.1
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• pp.55.5-55.5
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• 2019

We present our first attempt at understanding the dual impact of the large-scale density and velocity environment on the formation of very first astrophysical objects in the Universe. Following the recently developed quasi-linear perturbation theory on this effect, we introduce the publicly available initial condition generator of ours, BCCOMICS (Baryon Cold dark matter COsMological Inital Condition generator for Small scales), which provides so far the most self-consistent treatment of this physics beyond the usual linear perturbation theory. From a suite of uniform-grid simulations of N-body+hydro+BCCOMICS, we find that the formation of first astrophysical objects is strongly affected by both the density and velocity environment. Overdensity and streming-velocity (of baryon against cold dark matter) are found to give positive and negative impact on the formation of astrophysical objects, which we quantify in terms of various physical variables.

• Progress in Superconductivity and Cryogenics
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• v.11 no.2
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• pp.33-36
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• 2009

A 1 MW class HTS (High-Temperature Superconducting) synchronous motor has been developed. This motor is aimed to be utilized for industrial application such as large motors operating in large plants. The HTS field coil of the developed motor is cooled by way of neon thermo siphonmechanism and the stator (armature) coil is cooled by water through hollow copper conductor. This paper also describes evaluation of some electrical parameters from performance test results of our motor, which was conducted at steady state in generator mode and motor mode. Open and short circuit tests were conducted in generator mode while a 1.1 MW rated induction machine was rotating the HTS machine. Electrical parameters such as mutual inductance and synchronous inductance are deduced from these tests. Load test was done upto rating torque during motor mode and efficiency was measured at each load torque.

• Proceedings of the KIEE Conference
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• 1984.07a
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• pp.146-148
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• 1984

• Journal of the Korean Society of Propulsion Engineers
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• v.8 no.3
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• pp.10-16
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• 2004

Untypical unstable burning with very low frequency was observed at firing test of a gas generator using bundle cylindrical grain. The pressure unbalance between inside and outside of cylindrical grain brought such a low unstable burning. The grains were radially holed so that the high pressure gas inside of grain could quickly moved outward of gain, resulting dissipation of the pressure unbalance However too many holes were required to let the burning be stable for all operation regime from low to high temperature of grain and resultantly deteriorate the Progressive increase of gas amount produced by a gas generator. So another idea using grids located both sides of a bundle grain was applied to dissipate actively large vorticities enhanced by unbalance pressure distribution in a combustor. Finally stable burning with progressively increase of gas was established by application of 5${\times}$5 grid slightly away bundle grain to move bundle gain freely in case pressure unbalance were occurred inside of combustor.