• Journal of the Korean Society of Industry Convergence
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• v.26 no.3
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• pp.401-409
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• 2023

Oscillating water column (OWC) type wave power generator system is a power generation system that uses wave energy, a sustainable and renewable energy source. Irregular cycles and wave heights act as factors that make it difficult to secure generation efficiency of the wave power generator system. Recently, research for improving power generation efficiency is being conducted by applying digital twin technology to OWC type wave energy converter system. However, digital twin using sensor data can predict erroneous performance due to uncertainty in the sensor data. Therefore, this study proposes an uncertainty analysis method for sensor data which is used in digital twin to secure the reliability of digital twin prediction results. Uncertainty quantification considering sensor data characteristics and future uncertainty information according to uncertainty propagation were derived mathematically, and confidence interval estimation was performed based on the proposed method.

• Proceedings of the IEEK Conference
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• 2005.11a
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• pp.155-158
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• 2005

An invesitigation on power consumption of a mobile multimedia system using OFDM and MDVS technique is reported here. Analysis and simulation are performed to find the significances of proposed Microscopic Dynamic Voltage Scaling(MDVS) tehnique[4] on digital processor in terms of power saving. A study is also made to show power reduction in mobile multimedia system by incorporating OFDM modulation scheme in RF front-end. Finally, overall power consumption by functionally distinguished blocks ie. RF front-end, digital processor and human interface unit is shown here. Total power consumption is 8.2W for 2Mbps SD-quality WCDMA multimedia video service - the power consumption of digital processor is 3.9W(48%), the power consumption of RF front-end is 3.2W (36%), and the power consumption of interface is 1.8W(16%). Power saving of applying purposed MDVS technique is 35% in digital processor, and power saving of OFDM technique is 10-12dB in RF front-end.

• Proceedings of the KIEE Conference
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• 2002.07a
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• pp.59-62
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• 2002

Before a developed digital Power System Stabilizer(PSS) is installed to real power system, an efficient trial test for installing PSS is needed. In this paper, the performance of developed digital PSS for a single hydro-turbine generator and infinite bus system has been investigated using Real Time Digital Simulator(RTDS) in order to install PSS to real power system practically. The test system was composed of RTDS, three phase voltage/current amplifier and the PSS and the test scheme provided a very efficient way to verify the design and control performance of a PSS to be applied to real power system. The trial installation test through AVR 3% step test and three fault analysis may be guaranteed to install PSS to real power system.

• Proceedings of the KIPE Conference
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• 2005.07a
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• pp.106-108
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• 2005

High accuracy and stability digital controlled power supply for magnet is developed at PLS. This power supply has three sections. The first section is digital controller including DSP&FPGA and precision ADC, the second section consists of IGBT driver and four quad IGBT switch, and the third section is LC output filter section. AC input voltage of power supply is 3-phase 21V, output current is 0 ${\sim}$ 150 A dc. Switching frequency of four quad IGBT switch is 25 kHz. The output current of power supply has very high accuracy of 100 A step resolution at full range and the stability of +/- 1.5 ppm for short term and +/- 5 ppm for long term. This paper describes characteristics of filter and output current performance improvement after LC output filter at four quad digital power supplies.

• 제어로봇시스템학회:학술대회논문집
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• 1988.10a
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• pp.462-465
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• 1988

In this paper, it is described that digital back-up control system is developed and applied to the thermal power boiler control system which consists of many kinds of analog electronic cards. Also, by the installation of this system in ulsan power pllant, it was proven to have excellent capabilities of fault detection and digital back-up control.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.161-162
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• 2008

The steady state performance test for the digital protective relay using general relay test equipment has been main test methods. Because of the development of advanced power system testing equipments, dynamic performance test has been carried out additionally using a digital simulator such as RTDS(Real Time Digital Simulator). For the case of newly adopted digital protective relay with IEC 61850 and network, performance testing items need supplementing. This report displays testing items change according to newly protective relay.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.1304-1308
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• 2005

This paper presents the case that the existing analog control systems were retrofitted with digital DCS(Distributed Control System)s for boiler unit in thermal power plant. Replacement of existing worn-out or obsolete analog control systems has been considered. Replacement of existing analog control systems with another analog control systems has lots of difficulties in maintaining the systems due to being out of stock. Due to those difficulties, existing analog control systems have been retrofitted with digital DCSs in many industrial sites. KEPRI(Korea Electric Power Research Institute) accomplished the project that retrofitted analog control systems with the developed DCSs for boiler unit in middle-scale coal-fired thermal power plant. The benefits of an upgrade to digital control include a increase of reliability due to system redundancy, ease of modifying the control logic and the parameters of function block, ease of maintenance due to available spare parts, improvement of information display, ease of modifying MMI(Man Machine Interface) displays, a increase in system availability, and improvement of control performance. This paper describes how to use the parameters of existing analog controllers, the implementation of digital PID controller, control system configuration for boiler unit in thermal power plant, some boiler control loops, control result during commissioning, and the comparison of boiler characteristic test data after retrofitting with the existing test data.

• Proceedings of the KIEE Conference
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• 2003.11c
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• pp.563-566
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• 2003

We have designed the power control unit which belongs to the power cabinet and controls the power supplied to Control Rod Drive Mechanism(CRDM) as a digital system based on Digital Signal Processor(DSP). The power control unit dualized as the form of Master/Slave has had its increased reality. The Central Process Unit(CPU) board of a power control unit possesses two Digital Signal Processors(DSPs) of the control DSP for performing the tasks of power control and system monitoring and the communication of the Control DSP and the Communication DSP. To accomplish the functions requested in the power control unit effectively, we have installed Field Programmable Gate Arrays(FPGAS) on the CPU board and have FPGAs perform the memory mapping, the generation of each chip selection signal, the giving and receiving of the signals between the power controllers dualized, the fault detection and the generation of the firing signals.

• Proceedings of the KIPE Conference
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• 1998.10a
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• pp.575-580
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• 1998

A power meter is an instrument for measuring in watts the power flowing in a electric equipment. Since the value which a conventional power meter measures is analog, the power meter is hard to determine a phase difference between the voltage and current for a inductive load. The phase difference causes a loss of electric power and a increase of power-line load. In this paper, we propose a digital power meter using TI's DSP(Digital Singnal Processor) TMS320C5x, which is employed to calculate the phase difference and more accurate power consumption.

• Proceedings of the KIEE Conference
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• 1994.07a
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• pp.498-501
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• 1994

This paper presents a digital calculation method of instantaneous reactive power component for standby power supply(SPS) system. Reactive current is defined in time domain, calculated instantaneously by using a TMS320C25. The theoretical analysis is verified by the digital simulation and experimental results.