CDMA 기지국 beamforming 안테나 동작 시뮬레이션에 관한 연구 ( Simulation of the beamforming antenna operation applied to the DS-CDMA basestation system )

박재준,배병재,김재화,장태규 한국통신학회 1998 한국통신학회 학술대회논문집 Vol.- No.-

HF-CT센서를 이용한 고분자애자의 오손특성

박재준,Park, Jae-June 한국정보기술전략혁신학회 2005 情報學硏究 Vol.8 No.4

Investigations of high frequency current transformer(HF-CT) waveform characteristics of the surface leakage on kaolin polluted EPDM polymer insulators have been performed. This work is part of a program aimed at examining the potential for HF-CT waveform characteristics analysis to provide information about the environment contaminants and environment condition of polymer insulators. The investigation reported examined the HF-CT waveform characteristics at high frequencies. The use of high frequency measurements for on-line applications reduces electrical inference. This work was peformed utilizing HF-CT to monitor of surface polluted discharge. It was found that HF-CT waveform frequency spectrum, magnitude depend on importantly the duration of the surface discharge activity.

웨이블렛변환을 이용한 부분방전 종류의 특징추출에 관한 연구

박재준,Park, Jae-Jun 한국정보기술전략혁신학회 2003 情報學硏究 Vol.6 No.1

In this papers, we proposed the new method in order to diagnosis partial discharge type of transformers. For wavelet transform, Daubechie's filter is used,, we can obtain wavelet coefficients which is used to extract featrue of statistical parameters(maximum value, average value, dispersion, skewness, kurtosis) about high frequency current signal per 3-electrode type(needle-plane electrode, IEC electrode and Void electrode). Also, these coefficients are used to identify signal of internal partial discharge in transformer. As a result, from compare of high frequency current signal amplitude and average value, we are obtained results of IEC electrode> Void electrode> Needle-Plane electrode. Otherwise, in case of skewness and kurtosis, we are obtained results of Void electrode> IEC electrode> Needle-Plane electrode. As improved method in order to diagnosis partial discharge type of transformers, we use neural network.

고압전동기 고정자권선 결함 부분방전패턴

박재준,김희동,Park, Jae-Jun,Kim Hee-Dong 한국정보기술전략혁신학회 2004 情報學硏究 Vol.7 No.1

During normal machine operation, partial discharge(PD) measurements were performed with turbine generator analyzer(TGA) in imitation stator winding of high voltage motors. The motor was energized to 4.47kV, 6.67, respectively. Applied voltage to Imitation winding was used two voltage level, 4.47[kV] and 6.67[kV]. Motors having imitation stator winding were installed with 80pF capacitive couplers at the terminal box. Case of PD Pattern regarding applied voltage phase angel, the PD patterns were displayed two dimensional and three dimensional. TGA summarizes each plot with two quantities such as the normalized quantity number(NQN) and the peak PD magnitude(Qm). As the result, we could discrimidate using TGA the difference of internal and surface discharge for imitation stator winding. We have used the other technique, in order to feature extraction of faulty signals on stator winding, Daubechies Discrete wavelet transform and Harmonics analysis(FFT) about faulty signals.

고압전동기 고정자권선의 부분방전 특징추출

박재준,Park, Jae-Jun 한국정보기술전략혁신학회 2004 情報學硏究 Vol.7 No.4

On-line monitoring of fault discharge is an important approach for indicating the condition of electrical insulation of stator winding in high voltage motor. In this paper, several key aspects of on-line monitoring system are discussed, involving the characteristics of fault discharge of stator winding in high voltage motor, spectrum analysis of four simulation fault signals, feature extraction of internal fault discharge from apply voltage to breakdown. The study of the partial discharge activities allows to highlight the ageing stage in the winding fault under test. During the life of the winding insulation fault, the shape of PD signal change relating to the ageing stage. The ageing of stator winding insulation fault of high voltage motor is investigated based on the characteristics of partial discharge pulse distribution and statistical parameters, such as maximum, skewness and kurtosis using discrete wavelet trnasform coefficients.

영상신호처리 기법을 이용한 고압전동기 고정자권선 절연결함신호 분류

박재준,김희동,Park, Jae-Jun,Kim, Hee-Dong 한국전기전자재료학회 2007 전기전자재료학회논문지 Vol.20 No.1

Pattern classification of single and multiple discharge sources was applied using a wavelet image signal method in which a feature extraction was applied using a hidden sub-image. A feature extracting method that used vertical and horizontal images using an MSD method was applied to an averaging process for the scale of pulses for the phase. A feature extracting process for the preprocessing of the input of a neural network was performed using an inverse transformation of the horizontal, vertical, and diagonal sub-images. A back propagation algorithm in a neural network was used to classify defective signals. An algorithm for wavelet image processing was developed. In addition, the defective signal was classified using the extracted value that was quantified for the input of a neural network.

방사전자파를 이용한 고분자애자의 오손량 분류기법

박재준,Park Jae-Jun 한국전기전자재료학회 2006 전기전자재료학회논문지 Vol.19 No.2

Recently, diagnosis techniques have been investigated to detect a Partial Discharge associated with a dielectric material defect in a high voltage electrical apparatus, However, the properties of detection technique of Partial Discharge aren't completely understood because the physical process of Partial Discharge. Therefore, this paper analyzes the process on surface discharge of polymer insulator using wavelet transform. Wavelet transform provides a direct quantitative measure of spectral content in the time~frequency domain. As it is important to develop a non-contact method for detecting the kaolin contamination degree, this research analyzes the electromagnetic waves emitted from Partial Discharge using wavelet transform. This result experimentally shows the process of Partial Discharge as a two-dimensional distribution in the time-frequency domain. Feature extraction parameter namely, maximum and average of wavelet coefficients values, wavelet coefficients value at the point of $95\%$ in a histogram and number of maximum wavelet coefficient have used electromagnetic wave signals as input signals in the preprocessing process of neural networks in order to identify kaolin contamination rates. As result, root sum square error was produced by the test with a learning of neural networks obtained 0.00828.

에폭시/유기적으로 변경된 층상실리케이트가 충진 된 나노콤포지트의 유전특성

박재준,Park, Jae-Jun 한국전기전자재료학회 2008 전기전자재료학회논문지 Vol.21 No.2

Epoxy/Organically Modified Layered Silicate Nanocomposites were prepared by dispersing synthetic layered silicate modified with alkyl ammonium ions. In the dispersing process, the organically modified layered silicate were mixed in epoxy resin with shearing, and aggregation of the silicate were removed by centrifugal separation after mixing epoxy resin and silicates. Micrographs taken by transmission electron microscopy(TEM) indicate that the nanocomposites have a mixed morphology including both parallel silicate layers and exfoliated silicate layers area, As the thermal properties, the glass transition temperature of the nanocomposites was shifted to a higher temperature($+6^{\circ}C$)than pure epoxy. Furthermore, dispersion of OMLS will prevented relative permittivity from increasing at a high temperature above the glass transition temperature.

나노층상실리케이트가 충진된 에폭시-나노콤포지트의 열적특성 연구

박재준,Park, Jae-Jun 한국전기전자재료학회 2008 전기전자재료학회논문지 Vol.21 No.8

A large number of studies on the various characteristics of epoxy-layered silicate nanocomposites, such as electric and mechanical, morphology have been conducted and contributed to improve their characteristics. However, studies on the effects of its thermal conductivities in the thermal properties are not enough, even though there are some excellent evaluations for its insulation performances. Thermal properties will cause thermal degradation and significantly affect the reliability of these epoxy-layered silicate nanocomposites. In the results of the analysis of epoxy-layered silicate nanocomposites $T_g$ for various types of organoclays (10A, 15A, 20A, 30B, and 93A), it showed an excellent thermal property of 10A. Also, it represented low values in storage modulus and mechanical Tan (Delta) at a high temperature section 140$^{\circ}C$ and excellent thermal properties due to its movement to the high temperature section in the case of the property of 10A in the measurement of DMA elastics and mechanical losses. In the results of the measurement of thermal conductivities, power ultrasonic applications represented a significant increase in thermal conductivities in the case of the applications of power ultrasonic and planetary centrifugal mixers. Based on these results, it is necessary to perform related studies because it can be applied as useful materials for future power facilities applications in mold and impregnate insulation.

고압전동기 고정자권선의 절연결함에 대한 특징추출기법

박재준,이성룡,문대철,Park Jae-Jun,Lee Sung-Young,Mun Dae-Chul 한국전기전자재료학회 2006 전기전자재료학회논문지 Vol.19 No.10

Multi-resolution Signal Decomposition (MSD) Technique of Wavelet Transform has interesting properties of capturing the embedded horizontal, vertical and diagonal variations within an image in a separable form. This feature was exploited to identify individual partial discharge sources present in multi-source PD pattern, usually encountered during practical PD measurement. Employing the Daubechies wavelet, feature were extracted from the third level decomposed and reconstructed horizontal and vertical component images. These features were found to contain the necessary discriminating information corresponding to the individual PD sources and multi-PD soruces.