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전력용 변압기 보호용 시제품 IED 설계와 개선된 기법의 시험
朴哲圓(Chul-Won Park),申明澈(Myong-Chul Shin) 대한전기학회 2006 전기학회논문지 P Vol.55 No.1
A popular method used by primary protection for power transformer is current ratio differential relaying (RDR) with 2nd harmonic restraints. In modem power transformer due to the use of low-loss amorphous material, the 2nd harmonic component during inrush is significantly reduced. The higher the capacitance of the high voltage status and underground distribution, the more the differential current includes the 2nd harmonic component during internal fault. Thus the conventional method may not operate properly. This paper proposes an advanced relaying algorithm and the prototype IED hardware design and it's real-time experimental results. To evaluate performance of the proposed algorithm, the study is well constructed power system model including power transformer utilizing the EMTP software and the testing is made through simulation of various cases, The proposed relaying that is well constructed using DSP chip and microprocessor etc. has been developed and the prototype IED has been verified through on-line testing. The results show that an advanced relaying based prototype IED never mis-operated and correctly identified all the faults and that inrushes that are applied.
박철원(Chul-Won Park) 대한전기학회 2015 전기학회논문지 P Vol.64 No.1
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.
765㎸ 모델링 데이터에 의한 개선된 주파수 추정기법의 성능 평가
박철원(Chul-Won Park) 대한전기학회 2010 전기학회논문지 P Vol.59 No.3
The frequency is an important operation parameter for the control, protection, and stability of a power system. The frequency as a key index of power quality can be indicative of system abnormal conditions and disturbances. Due to the sudden change in generation and loads or faults in power system, the frequency is supposed to deviate from its nominal value. It is essential that the frequency must be maintained very close to its nominal frequency. An accurate monitoring of the power frequency is essential to optimal operation and prevention for wide area blackout. As most conventional frequency estimation schemes are based on DFT filter, it has been pointed out that the gain error could cause defects when the frequency is deviated from nominal value. This paper presents an advanced frequency estimation technique using gain compensation to improve the performance of DFT filter based techniques. To evaluate performance of the proposed algorithm, the 765㎸ T/L system in Korea is simulated by EMTP-RV software. The proposed technique can reduce the gain error caused when the power system frequency deviates from nominal value.
박철원(Chul-Won Park) 대한전기학회 2016 전기학회논문지 P Vol.65 No.1
In order to service restoration and enhance power system reliability, a number of impedance based fault location algorithms have been developed for fault locating in a transmission line. This paper presents an advanced impedance-based fault location algorithms in a two-ended sources transmission line to reduce the DC offset error effects. This fault location algorithm uses of the GPS time synchronized voltage and current signals from the local and remote terminal. The algorithm uses an advanced DC offset removal filter. A series of test results using ATPdraw simulation data show the performance effectiveness of the proposed algorithm. The proposed algorithm is valid for a two-end sources transmission network.
디지털 보호계전기의 시험을 위한 시뮬레이터에 관한 연구
朴哲圓(Chul-Won Park),申明澈(Myong-Chul Shin),安泰豊(Tae-Pung Ahn) 대한전기학회 2006 전기학회논문지 P Vol.55 No.4
In this work. the digital simulator for testing of digital protective relay is presented. The proposed simulator software has EMTP simulation data file conversion, sequence waveform generation. user define simulation data generation, communication engine, data analysis engine and measurements function etc. The simulator hardware is designed using 32bit floating point DSP architecture to achieve flexibility and high speed operation. This simulator is tested to evaluate the performance of relay simulator by using a output data of simulation model on EMTP.
朴哲圓(Chul-Won Park),申光哲(Kwang-Chul Shin),申明澈(Myong-Chul Shin) 대한전기학회 2008 전기학회논문지 P Vol.57 No.2
AC generator plays an important role of power system. The large AC generator fault may lead to large impacts or perturbations in power system. And then the protection of a generator has very important role in maintaining stability in a power system. In present, the DFT(discrete Fourier transform) based RDR(ratio differential relay) had been widely applied to a internal fault of a generator stator winding. But DFT has a serious drawback. In the course of transforming a target signal to frequency domain, time information is lost, DWT uses a time-scale region. This paper proposes an advanced fault detection algorithm using DWT(discrete Wavelet transform) to enhance the drawback of conventional DFT based relaying. To evaluate the performance of the proposed relaying, we used the test data which were sampled with 720 [㎐] per cycle and obtained from ATP(alternative transient program) simulation. And we made a comparative study of conventional DFT based RDR and the proposed relaying.
교류 발전기 고정자 사고 검출을 위한 최적 마더 웨이브릿의 선정
朴哲圓(Chul-Won Park) 대한전기학회 2008 전기학회논문지 P Vol.57 No.4
For stator winding protection of AC generator, KCL(Kirchhoff's Current Law) is widely applied. Actually a CRDR(Current Ratio Differential Relay) based on DFT(Discrete Fourier Transform) has been used for protecting generator. It has been pointed out that defects can occur during the process of transforming a time domain signal into a frequency domain one which can lead to loss of time domain information. Wavelets techniques are proposed for the analysis of power system transients. This paper introduces an algorithm to choose a suitable Mother Wavelet for generator stator fault detection. For optimal selection, we analyzed db(Daubechies), sym(Symlets), and coif(Coiflects) of Mother Wavelet. And we compared with performance of the choice algorithm using detail coefficients energy and RMS(root mean square) error. It can be improved the reliability of the conventional DFT based CRDR. The feasibility and effectiveness of the proposed scheme is proved with simulation using collected data obtained from ATP (Alternative Transient Program) package.