• Journal of Energy Engineering
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• v.6 no.1
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• pp.41-51
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• 1997

A dynamic mathematical model of a thermal power plant with a single drum-type boiler is described with the base on modular concept. The present process model, which is including full scope of the components and high load changes, is based on physical approach through lumped parameters. The module, which means a component of the power plant and must essentially depict the characteristics of the component well, might be interconnected using pressure nodal method in a arrangement determined by users. With the results of the load changes of 75 MW to 95 MW and 95MW to 75 MW with the rate of 3 MW/min, the applicability of the process model is examined connecting to DCS(Dispersion Control System), which has a real running logic of 100 MW real power plant.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.60 no.4
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• pp.241-245
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• 2011

In this paper, when photovoltaic (PV) systems are connected to power distribution system, most effective capacity and connected-point of PV system are presented considering power distribution system reliability. The reliability model of PV system is presented considering the duration of sunshine. Also the model of time-varying load and reliability test system bus2 model are used. To simulate the effects of PV system, various cases are selected; (1) base case which is no connection of PV system to power distribution system when faults are occurred, (2) 3MW case which is 3[MW] connection of PV system (3) 4[MW] case, and (4) 20[MW] case which is 20[MW] connection of PV system to the bus of power distribution system. The capacity limit of connected PV system is settled to 14[MW] for all cases except case 4. The reliability for residential, general, industrial, and educational customer is evaluated.

• Journal of the Korean Society of Visualization
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• v.17 no.2
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• pp.32-38
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• 2019

A comparison study between computational-fluid-dynamics simulation and wind tunnel test for a megawatt-class wind turbine is conducted. For the study, flow-field in wake, basic aerodynamic performance, and effect of the yaw error for a 1/86 scaled-down model of the NREL offshore 5 MW wind turbine are numerically calculated using commercial software "FloEFD" with $k-{\varepsilon}$ turbulence model. The computed results are compared to the wind tunnel test performed by the constant-velocity mode for the model. It is shown that discrepancy are found between the two results at lower tip-speed ratio and higher yaw angle, however, the velocity-defection distribution in the wake, the torque coefficient at moderated and high tip-speed ratios are in good agreement with the wind tunnel test.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.63 no.3
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• pp.163-168
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• 2014

In this paper, when photovoltaic systems are connected to distribution system, most effective capacity and location of PV system are studied considering customer interruption costs of power distribution system. The reliability model of PV system considering the duration of sunshine, the model of time-varying load and Roy Billinton test system (bus2 model) are used. To simulate the effects of PV system, various cases are selected; (1) base case which is no connection of PV system to power distribution system when faults are occurred, (2) 3MW case which is 3[MW] connection of PV system (3) 4[MW] case, and (4) 20[MW] case which is 20[MW] connection of PV system to the bus of power distribution system. The capacity limit of connected PV system is settled to 14[MW] for all cases except case 4. The reliability and customer interruption costs for residential, general, industrial, and educational customer is evaluated.

• Journal of Energy Engineering
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• v.26 no.2
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• pp.99-120
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• 2017

In SS branch of Korea District Heating Corporation, Combined Heat & Power power plant with 99MW capacity and 98Gcal / h capacity is operated as a district electricity business. In this region, it is difficult to operate the generator due to the problem of surplus heat treatment between June and September due to the economic recession and the decrease in demand, so it is urgent to develop an economical energy new business model. In this study, we will develop an optimized operation model by introducing a renewable energy hybrid system based on actual operation data of this site. In particular, among renewable energy sources, fuel cell (Fuel Cell) power generation which can generate heat and electricity at the same time with limited location constraints, photovoltaic power generation which is representative renewable energy, ESS (Energy Storage System). HOMER (Hybrid Optimization of Multiple Energy Resources) program was used to select the optimal model. As a result of the economic analysis, 99MW CHP combined cycle power generation is the most economical in terms of net present cost (NPC), but 99MW CHP in terms of carbon emission trading and renewable energy certificate And 5MW fuel cells, and 521kW of solar power to supply electricity and heat than the supply of electricity and heat by 99MW CHP cogeneration power, it was shown that it is economically up to 247.5 billion won. we confirmed the results of the improvement of the zone electricity business condition by introducing the fuel cell and the renewable energy hybrid system as the optimization process model.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.30 no.4
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• pp.191-199
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• 2018

In this paper, wind data at 20 locations are collected and analyzed in order to review optimal candidate site for offshore wind farm around Korean marginal seas. Observed wind data is fitted to Rayleigh and Weibull distribution and annual energy production is estimated according to wind frequency. As the model of wind turbine generator, seven kinds of output of 1.5~5 MW were selected and their performance curves were used. As a result, Repower-5 MW turbines showed high energy production at wind speeds of 7.15 m/s or higher, but G128-4.5 MW turbines were found to be favorable at lower wind speeds. In the case of Marado, Geojedo and Pohang, where the rate of occurrence of wind speeds over 10 m/s was high, the capacity factor of REpower's 5 MW offshore wind turbine was 56.49%, 50.92% and 50.08%, respectively.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.11b
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• pp.826-831
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• 2001

Electromagnetic forces generate vibrations in the end-winding of large generators. A finite element analysis using a commercial S/W is performed to calculate electromagnetic force of end-winding in two pole generator for 500 MW fossil power plant. Also, this paper presents analytical and experimental modal analysis results of generator end- winding. Using validated FE model, 3D electromagnetic model which computes the forces on the end-winding is coupled with a 3D mechanical model which calculates the dynamic displacement and stress under electromagnetic forces. These results will be used to evaluate reliability of end-winding and applied to update model.

• Journal of Advanced Marine Engineering and Technology
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• v.35 no.8
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• pp.1063-1069
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• 2011

This paper presents aerodynamic power outputs of wind turbine of 6 MW wind farm composed of 3 sets of 2 MW wind turbine according to the separation distance by using CFD. Layout design including offshore wind farm and onshore wind farm is key factor for the initial investment cost, annual energy production and maintenance cost. For each wind turbine rotor, not actuator disc model with momentum source but full 3-dimensional model is used for CFD and it has a great technical meaning. The results of this study can be applied to the offshore wind farm layout design effectively.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.66 no.3
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• pp.110-116
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• 2017

System to automate the trial-run of energy storage system for frequency regulation was developed and demonstrated. Basic strategy was developed on the basis of trial-run procedure and verified in the computer simulation tool. The algorithm was developed and coded for 4MW trial-run automation system. 4MW trial-run automation system was connected to 4MW energy storage system for frequency regulation in Jocheon substation of Jeju city and demonstrated. 24MW trial-run automation system was developed on the basis of 4MW trial-run automation system and verified by operation system for 24MW energy storage system for frequency regulation. The operation system has own simulation model of energy storage system and power system. The verification was performed to improve the system in the view of user. 24MW trial-run automation system was demonstrated in 32MW Ul-san and 36MW Non-gong energy storage system. All tests of trial-run was done by manual and first they ware taken 1 week with no trial-run automation system. The manual trial-run tests were taken by maximum three times. Trial-run test by trial-run automation system was taken 2 days. The system helps reduce the trial-run test period and improve the accuracy of tests.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.45 no.2
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• pp.85-91
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• 2017

A wind tunnel test for 1/86 scaled down model of the NREL 5 MW offshore wind turbine was conducted to investigate the wake and flow fields. Deficit of flow speed in the wake region and variations of the turbulence intensity were measured using a hot wire anemometer at rated tip speed ratio of 11.4 m/s and a rotational speed of 1,045 rpm. According to the test results, velocity deficits along both of lateral and vertical directions were recovered within 2 rotor radii downstream from the rotating disc plane. The tip vortices effect was negligible after 5 rotor radii downstream from the rotating plane. Turbulence intensities showed maximum value around the blade tip, and decreased rapidly after one radius apart from the rotating plane, and those values were preserved until 6 rotor radii downstream.