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고장전류의 웨이브릿 변환을 이용한 동기 발전기 보호 알고리즘
朴哲圓(Chul-Won Park),申明澈(Myong-Chul Shin) 대한전기학회 2007 전기학회논문지 Vol.56 No.5
A generator plays an important role in transferring an electric power to power system networks. The generator protection systems in Korea have been imported and operated through a tum-key from overseas entirely. Therefore, a study of the generator protection field has in urgent need for a stable operation of the imported goods, and for preparation of next generation protection system. The paper describes the fault detection algorithm using WT(Wavelet Transform) of currents for a generator protection. The fault current signals after executing a terminal fault modeling collect using a MATLAB package, and calculate the wavelet coefficients through the process of a multi-level decomposition (MLD). The proposed algorithm for a fault detection using the Daubechies WT (wavelet transform) was executed with a C language for the command line function and for the real time realization after analyzing MATLAB's graphical interface. The advanced technique had complemented the defects of a DFT by applying a Daubechies WT, and had improved faster a speed and more accurate of fault discriminant than a conventional DFR.
朴哲弘(Park Cheol-hong),柳姃我(Lyu Jeong-ah) 대한한의학원전학회 2018 대한한의학원전학회지 Vol.31 No.3
Objectives : Contents regarding Qiuzimen as found in Beijiqianjinyaofang and Qianjinyifang were studied for their potentialities to be applied to infertility clinics. Methods : The contents on Qiuzimen in Beijiqianjinyaofang and Qianjinyifang are pondered upon after dividing into two categories of medical theory and therapeutic principle, and other related texts and dissertations are further studied to discover a potential subject matter in being applied to today s modern clinics. Results : 1. In medical theory, Sunsimiao picked five overexertions and seven damages as the main medical cause of infertility. For remedy, he established four common formula, which are: chinjasan, bakchotangpotang, suppository, and haseog(cheon)moondongwhan. 2. There are total of thirteen types of formula described in the Qiuzimen in Beijiqianjinyaofang and Qianjinyifang, and five acupuncture points are used in the moxibustion method. After analyzing the herbs that were used six or more times, it was discovered that medicines were used to tonify the viscera of heart and kidney that are damaged through five overexertions and seven damages. In moxibustion method, different points such as CV4, LR14, pomoon, cheonmoon, and KI2, which is the point for kidney meridian were used in order to tonify the uterus through lower abdomen area and reproductive organs. 3. Qiuzimen has not only had a great impact on the infertility treatment as found in Furendaquanliangfang, which is the first gynecology text in Song dynasty, but it also had a continuous impact on medical texts in Ming and Qing dynasty. 4. The infertility therapeutic principle and approach method as found in the Qiuzimen are still relevant in today s modern infetility treatment. Conclusions : In the Qiuzimen of Beijiqianjinyaofang and Qianjinyifang, the problem of infertility is viewed as the whole body s problem, namely a type of defective disease caused by five overexertions and seven damages, the view of which should be applied to today s modern clinics.
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.
발전기시스템의 고정자보호 IED를 위한 개선된 알고리즘
朴哲圓(Chul-Won Park) 대한전기학회 2008 전기학회논문지 P Vol.57 No.2
The large AC generator fault may lead to large impacts or perturbations in power system. The generator protection control systems in Korea have been imported and operated through a tum-key from overseas entirely. Therefore a study of the generator protection field has in urgent need for a stable operation of the imported goods. In present, the algorithm using the current ratio differential relaying based DFT for stator winding protection or a fault detection had been applied that of internal fault protection of a generator, the DFT used for the analysis of transient state signal conventionally had defects losing a time information in the course of transforming a target signal to frequency domain. In this paper, the discrete wavelet transform (DWT) was applied a fault detection of the generator being superior to a transient state signal analysis and being easy to real time realization. The fault signals after executing a terminal fault modeling collect using a MATLAB package, and calculate the wavelet coefficients through the process of a multi-level decomposition (MLD). The proposed algorithm for a fault detection using the Daubechies WT (wavelet transform) was executed with a C language and the commend line function for the real time realization after analyzing MATLAB's graphical interface. The advanced technique had improved faster a speed of fault discrimination than a conventional DFR based on DFT.