• Transactions on Electrical and Electronic Materials
• /
• 제9권5호
• /
• pp.186-192
• /
• 2008

Cross linked polyethylene (XLPE) insulators are used as insulation in ultra-high voltage electric power cables. This study investigated the electrical properties of XLPE at different temperatures. The electrical properties of the changing tree phenomenon was examined as a function of temperature applied to the electrical conductors by measuring the partial discharge at $25^{\circ}C$ to $80^{\circ}C$ and applied voltages to the electrodes ranging from 1 kV to 40 kV. The activity of the partial discharge was examined at various temperatures using the K-means distribution. The results revealed the specimen at $80^{\circ}C$ to have the lowest inception voltage and breakdown voltage. In addition, the core of clusters was moved $0^{\circ}$ and $180^{\circ}$ at the positive region and $180^{\circ}$ and $360^{\circ}$ in the negative region in the K-means. The distribution of clusters was concentrated on the inception condition and spread out widely at the breakdown voltage.

• 전기학회논문지
• /
• 제66권9호
• /
• pp.1392-1401
• /
• 2017

In this study, the design methodology of pattern classification is introduced for avoiding faults through partial discharge occurring in the power facilities and local sites. In order to classify some partial discharge types according to the characteristics of each feature, the model is constructed by using the Radial Basis Function Neural Networks(RBFNNs) and Particle Swarm Optimization(PSO). In the input layer of the RBFNNs, the feature vector is searched and the dimension is reduced through Principal Component Analysis(PCA) and PSO. In the hidden layer, the fuzzy coefficients of the fuzzy clustering method(FCM) are tuned using PSO. Raw datasets for partial discharge are obtained through the Motor Insulation Monitoring System(MIMS) instrument using an Epoxy Mica Coupling(EMC) sensor. The preprocessed datasets for partial discharge are acquired through the Phase Resolved Partial Discharge Analysis(PRPDA) preprocessing algorithm to obtain partial discharge types such as void, corona, surface, and slot discharges. Also, when the amplitude size is considered as two types of both the maximum value and the average value in the process for extracting the preprocessed datasets, two different kinds of feature datasets are produced. In this study, the classification ratio between the proposed RBFNNs model and other classifiers is shown by using the two different kinds of feature datasets, and also we demonstrate the proposed model shows superiority from the viewpoint of classification performance.

• 전기학회논문지
• /
• 제65권6호
• /
• pp.1083-1088
• /
• 2016

25.8kV GIS part generated by sensors to measure contact an inflow of noise depending on the extent of the measured discharge occurs often not easy. Partial discharge signal measurement sensor suitable for developing a more useful measurements at the scene to this, partial discharge waveform analysis developed a sensor, and to utilize forSensor on the development of the most important is VSWR decided to (voltage standing wave ratio) voltage standing-wave ratio less than 1.5 and decided less than at the full spectrum bands that are measured, this time Return loss, as measured value by absolute criteria 14.0 dB produced the sensor, designed to or more. UHF 1.5~0.5 GHz bandwidth spectrum to be measured in GIS. UHF bands were designed to be able to measure the best signal. Recently, 25.8kV GIS production company has been increasing variety of GIS were made open spacer in partial discharge in accordance with the not very easy to detect the signal. The sensor is designed height of four cm external spacer is attachment GIS in an influx of outside noise measurement, and be so manufactured as to facilitate the least we've done. Also, since partial discharge which occur can measure the frequency of the 170kV GIS external partial-discharge signals that occur at the scene of insulation applied to the spacer. Features, and also derived good results using global positioning. Also measured discharge point about sensors that are stable and the reliability of the development and local substation equipment failure occurring signal analysis through the discharge for the prevention of widely. There should be to believe that used.

• 한국전기전자재료학회논문지
• /
• 제28권1호
• /
• pp.46-50
• /
• 2015

The cable degradation process is largely divided into three steps; Step 1 : Thermal degradation, Step 2 : Weibull degradation, Step 3 : Partial discharge. it is progress in step order. This article aims to explain the process of cable degradation using the method of insulation resistance and accordingly to compose and manufacture a system of measuring the life of electrical cable. Before measuring the insulation resistance, a system of measuring the temperature and current of cables was made, and the established system was installed for test on the site of a power plant to collect the measured data. The current sensor was used TFC30P80A-CL420, and temperature sensor was used the DK-1270 PT100 sensor as RTD sensor. When measured the temperature and the load current at the same position, was confirmed that in case of the load current value was high, also temperature value high. Therefore, the correlation between load currents and temperature was verified, and the analysis of diagnostic data was evaluated, which could be utilized in identifying the fault condition of cable systems.

• 한국초전도ㆍ저온공학회논문지
• /
• 제3권2호
• /
• pp.27-31
• /
• 2001

This paper deals with the numerical estimation of the bubble behavior and the partial discharge (PD) initiation voltage on the basis of electric field calculation with the coaxial coil layer-to-cylindrical electrode system for the simulation of high temperature superconducting coils. The theoretical results of bubble behavior and the PD initiation voltages show fairly good agreement with the experimental results.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2000년도 학술대회 논문집 전문대학교육위원
• /
• pp.40-43
• /
• 2000

Our studies diagnose insulation degradation using the method of computer sensing system, which has the advantages of PD(partial discharge) and AE(acoustic emission) sensing system. To use advantages of these two methods can be used effectively to search for treeing location and PD in some materials. In analysis method of degradation, using statically operator such as the center of gravity (G), the gradient of the discharge distribution(C), we have analyzed for the prediction of life which we can be obtained the time, occurred of many pulse of small discharge amplitude.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2002년도 추계학술대회 논문집 전기기기 및 에너지변환시스템부문
• /
• pp.157-159
• /
• 2002

In order to obtain reliability and extend life of GAS Voltage Transformer in GIS, it has to prevent aging by overvoltage considered to insulation characteristics of insulating material. This paper describes some characteristics of V-T characteristics and partial discharges.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2005년도 제36회 하계학술대회 논문집 B
• /
• pp.975-977
• /
• 2005

The generator on-line diagnosis system has been developed. This system monitor the insulation condition of stator winding by on-line measurements of partial discharge and the shorted-turn condition of rotor winding by on-line measurements of slot leakage flux. Sensor, such as SSC(Stator Slot Coupler) and flux probe are used for generator on-line diagnosis.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1991년도 추계학술대회 논문집 학회본부
• /
• pp.415-418
• /
• 1991

This paper described an instrument for the detection and geometric location of partial discharge(PD) sources in oil transformer. This instrument measures electric current pulse and ultrasonic pulse simultaneously in order to determine the geometric location of PD in transformer. Laboratory experiment systems are made for detection and location of PD in oil transformer. It was observed that there are effects of the barrier, such as insulation papers, silicon steel plate and actual transformer with location and detection of PD in model transformer. Through the laboratory actual test, it was clarified that this measurement device could be used satisfactorily for location of pd in oil transformer.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2009년도 제40회 하계학술대회
• /
• pp.1381_1382
• /
• 2009

Nondestructive tests were performed on two 4.16kV motors. Epoxy-mica coupler(80pF) was connected to 4.16 kV motor stator windings. The voltage applied to the stator windings was 2.4 kV, 3.0kV, 3.5kV and 4.16kV, respectively. Digital partial discharge detector(PDD) and turbine generator analyzer(TGA) were used to measure partial discharge(PD) activity. TGA summarizes each plot with two quantities such as the normalized quantity number(NQN) and the peak PD magnitude(Qm). The PD levels in pC were measured with PDD. PD patterns of stator windings were indicated the internal discharge. PD patterns are consistent with the result of measurement using PDD and TGA.