• Proceedings of the Korean Nuclear Society Conference
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• 1998.05a
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• pp.321-328
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• 1998

A controller and sensor fault tolerant system jot a steam generator is designed with fuzzy logic. A structure of the : proposed fault tolerant redundant system is composed of a supervisor and two fuzzy weighting modulators. A supervisor alternatively checks a controlled and a sensor induced performances to identify Which Part, a controller or a sensor, is faulty. In order to analyze controller induced performance both an error and a charge in error of the system output an chosen as fuzzy variables. The fuzzy logic jot a sensor induced performance uses two variables : a deviation between two sensor outputs and its frequency, Fuzzy weighting modulator generates an output signal compensated for faulty input signal. Simulations show that the : proposed fault tolerant control scheme jot a steam generator regulates welt water level by suppressing fault effect of either controllers or sensors. Therefore through duplicating sensors and controllers with the proposed fault tolerant scheme, both a reliability of a steam generator control and sensor system and that of a power plant increase even mote.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.62 no.3
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• pp.133-138
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• 2013

A large generator is an important role in transferring an electric power to power system. The IEDs of large generator often use microprocessor technology to obtain a digital relay system with a wide range of measuring, protection, control, monitoring, and communication functions. However, all generator protection and control systems in Korea imported from abroad and are being operated. In order to reduce the large expense and improve the reliable operation, development of generator protection and control system by domestic technology is required. This paper deals with the design of the IED of generator protection panel for development of generator protection and control system. The major emphasis of the paper will be on the description of hardware and signal processing test results and measurement accuracy of the prototype IED. By developing of generator IED based on DSP and microprocessor, replacement of the generator protection panel imports are expected to be effective.

• Proceedings of the KIEE Conference
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• 1995.07c
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• pp.1299-1303
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• 1995

The detection and measurement of partial discharge activity prevalent in the solid insulating systems of high-voltage generator stator windings has, for many years, been a recognized method of assessing the insulation condition of such systems. Partial discharge activity occurs at sites of degradation within, or at the surface of, stator's insulation systems under high voltage stressing. However, partial discharge pulses suffer from attenuation and distortion when transmitted along windings, because of the complex L-C network between windings. The mode of transmission varies with the signal frequency and is dependant on the geometrical configurations of windings. This paper reports the investigated results of the signal propagation characteristics along the windings when both sinusoidal signals and simulated partial discharge pulses are injected at the various positions of stator windings within the 25 MVA, 11 kV hydro generator. The on-line identification technique of partial discharge location in generator windings is also proposed in this study.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.64 no.1
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• pp.35-40
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• 2015

Generators are the most complex and expensive single element in a power system. The generator protection relays should to minimize damage during fault states and must be designed for maximum reliability. A conventional CDR(Current Differential Relaying) technique based on DFT(Discrete Fourier Transform) filter have the disadvantages that the time information can lead to loss in the process of converting the signal from the time domain to the frequency domain. A WT(Wavelet transform) and WT analysis is known that it is possible with the local analysis of the fault and transient signal. In this paper, to overcome the defects in the DFT process, an application of WT for fault detection of generator is presented. This paper describes an selection of mother Wavelet to detect faults of generator. Using collected data from the fault simulation with ATPdraw, we analyzed the several mother Wavelet through the course of MLD(multi-level decomposition) using MATLAB software. Finally, it can be seen that the proposed technique using detail coefficient of Daubechies level 2 which can be fault discriminant of generator.

• Transactions of the Korean Society of Pressure Vessels and Piping
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• v.8 no.3
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• pp.7-12
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• 2012

Steam generator tubes are critical boundary of the primary and secondary side in nuclear power plants. Eddy current testing is commonly used as the method of non-destructive testing for the safety and integrity of steam generator tubes in the nuclear power plants. Changes in the geometric shape act as a stress concentration factor likely to cause a defect during the steam generator operation. The mixed-signals with the geometric shape are distorted and attributes that are difficult to detect signals. An example is bending stress due to compression process at a U-bend occurring in the intrados region which has a small radius of curvature. The resulting change in the geometric shape may lead to a dent like occurrences. The dent can cause stress concentration and generates stress corrosion cracks. In this study, the steam generator tubes of nuclear power plant were selected to study for analysis of mixed-signal containing dent and stress corrosion cracks.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.10
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• pp.2163-2170
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• 2012

A signal receiving system can measure and analyze frequency, pulse modulation, scan modulation, frequency modulation on pulse, phase modulation on pulse of RF signal. A signal receiving system should be verified under simulated RF signal environment prior to verification on operation in fields. This paper describes an effective method to generate simulated RF signals with considering operational scenario. The simulated RF signal generator can be effectively used to evaluate the performance of the signal receiver and reduce the test cost of the signal receiver.

• Journal of Positioning, Navigation, and Timing
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• v.5 no.3
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• pp.109-118
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• 2016

The present paper proposes a method that can estimate a roll rate of spinning vehicles utilizing GPS receivers. The proposed method analyzes a relation between received signal and correlation value and utilizes a phenomenon that received signal power that changes according to a signal incident direction affects a correlation value. That is, a roll-rate estimation method using zero crossing detection method for correlation value, which has sinusoidal periodicity according to rotations of vehicles, is proposed. A correlation value in real environments experiences a jitter so that the proposed method includes a pre-processing filter and detection threshold setting way is also considered to reduce the effect of received signal power. In order to verify the operation of the proposed method and analyze the performance, a signal generator and software-defined receiver (SDR) are designed. The signal generator generates intermediate frequency (IF) signal by taking the rotation of vehicles, antenna gain, and signal power into consideration, and a correlation value is acquired by taking the generated IF signals into consideration. Using the generated correlation value, the operation of the proposed roll rate estimation method is verified and the performance is analyzed.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.39 no.9
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• pp.28-34
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• 2002

In this paper, a new type predistorter using a low frequency intermodulation signals terms of harmonic generator is proposed. A vector modulator, in which fundamental signal is modulated with low frequency intermodulation signals derived from harmonic generator, generates predistorted third and fifth IM components. Using predistorted signals, intermodulation distortion signals of power amplifier suppressed. The suggested predistorter has been manufactured to operate in Korean PCS base-station transmitting band (1840~1870MHz). The test results show that the third IMD signal level is reduced more than 20dB and the fifth IMD signal is reduced about 10dB for CW two-tone signals. The predistorter improves the Adjacent Channel Power Ratio (ACPR) more than 10dB for CDMA (IS-95) signals.

• The Journal of the Korea institute of electronic communication sciences
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• v.17 no.5
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• pp.841-852
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• 2022

In this paper, a 3-phase inverter output waveform generator based on SPWM control was developed to verify the performance of the LCL filter. In order to obtain a test signal for verifying the performance of the filter, first, a DSP-based 3-phase SPWM signal generation algorithm was developed, and then a three-phase voltage source inverter circuit was designed using three half-bridge gate drivers. Next, one LCL filter was experimentally fabricated to verify the effectiveness of the developed SPWM-based 3-phase inverter output waveform generator as a test signal generator, and a DSP-based performance verification system was experimentally constructed. Finally, by comparing the three-phase voltage waveform before and after the LCL filter obtained in the output control experiment with the given time ratio, the effectiveness of the SPWM-based 3-phase inverter output waveform generator was verified.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.19 no.3
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• pp.157-163
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• 2019

A small millimeter-wave tracking radar is a pulse radar that searches, detects, and tracks a target in real time through a TWS (Track While Scan) method on a sea-going traps target with a large RCS running at low speed. This paper describes the development of a simulated signal generator to verify the performance of a small millimeter wave tracking radar in laboratory anechoic chamber environment. We describe a GUI program for testing and performance analysis in conjunction with hardware configuration and tracking radar, and verified the simulated signal generator implemented through performance test.