• KEPCO Journal on Electric Power and Energy
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• 제2권1호
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• pp.43-47
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• 2016

This system is a diagnosis system that checks whether it causes a partial discharge of a power cable or not. It is to classify normal from abnormal-normal, PD (Partial Discharge) sound through analysis of RLCR (Relative Level Crossing Rate) and spectrogram energy algorithm. Partial discharge diagnostic system has a function that stores PD sound and analyzes the data. The wave shape of PD sound is similar to noise and is systematically generated by partial discharge. Therefore, in this paper, we could discreminate between normal and abnormal case using relative level crossing rate (RLCR) and spectrogram of frequency energy rate.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1996년도 추계학술대회 논문집
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• pp.283-286
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• 1996

A signal generated by partial discharge in low density Polyethylene (LDPE) and cross- linked polyethylene (XLPE) has been detected by ultrasonic sensors. The observed signal is analysed with the quantity of partial discharge, number of peaks, and energy ($\Sigma$y$^2$). It was found that signals between LDPE and XLPE are quite different and that the signal of XLPE has very long duration time and rising time, and that the quantity of partial discharge of XLPE is saturated. It was also found that tree retardant XLPE (TR-XLPE) has lower quantity of partial discharge, number of peaks, and energy than naturalal XLPE.

• 한국전자통신학회논문지
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• 제10권3호
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• pp.349-356
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• 2015

광학적 잡음과 전기적 잡음을 복합적으로 제거할 수 있는 하이브리드 필터를 채용하고 펄스형태의 아크 광 신호를 적분하여 수신되는 아크에너지의 크기로 감지할 수 있는 원격감시 기능을 갖는 고감도 부분방전 센서를 구현하였다. 하이브리드 필터는 부분방전 센서가 설치되는 배전반 내 환경에서 내부 형광등과 백열등 조명에 대하여 영향을 받지 않음을 보여주었다. 종래에는 아크광의 불규칙한 파형특성으로 인하여 첨두치가 감지되어 아크광의 크기에 비례한 선택적 감지가 어려웠으나, 센서에 적용된 적분연산 기능은 각기 다른 아크광의 에너지 레벨에 대하여도 선택적으로 감지가 가능함을 실험적으로 보여주었다. 센서는 2m 이격된 원격지에서 100A 저압 MCCB의 정상 개폐 시 발생하는 섬광에 해당하는 광 에너지에 대해서도 감지가 가능함을 보여주어 원격감시 기능을 갖는 고감도 부분방전센서에 적용 가능함을 보여주었다.

• 전기학회논문지
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• 제58권9호
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• pp.1784-1789
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• 2009

This paper describes the measurement technology of the dissolved hydrogen gas due to partial discharge in oil using gas sensor. For higher resolution and less error in measurement of the dissolved hydrogen gas in oil, the sensor outputs with ambient temperature which affect the sensor output characteristics should be considered. The sensor output trends with ambient temperature and the properties of the dissolved hydrogen gas in oil with partial discharge characteristic were analyzed through the test results. It was indicated that the sensor peak and the base voltage with measuring time were affected by ambient temperature and the measurement errors of the sensor output by temperature were reduced by using the difference between the peak and the base voltage rather than just the peak voltage. In addition, the hydrogen gas sensor outputs were increased with the increase of partial discharge energy.

• 전자공학회논문지
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• 제54권1호
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• pp.157-163
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• 2017

본 논문은 주파수대역검출센서(FBDS)를 이용하여 전력 케이블에서 부분방전(PD)가 발생했을 때 이것을 검출하고 진단하는 시스템 개발에 관한 논문이다. 주파수대역검출센서는 각 주파수대역에서 발생하는 부분방전을 음향학적으로 변환하여 검출한다. 부분방전은 그 음향학적 신호 형태로 잡음과 유사하다. 따라서 본 논문에서 상대적 레벨교차율(RLCR)과 주파수에너지 스펙트럼을 이용하여 정상과 비정상을 구별하여 부분방전을 검출하였다.

• Journal of Electrical Engineering and Technology
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• 제10권3호
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• pp.1093-1101
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• 2015

Partial Discharge (PD) is a physical phenomenon, which causes defects and damages to the insulation. This phenomenon is regarded as the most important source of fault and defect in power transformers. Therefore, methods of high speed and precision are considered of special importance for the maintenance of transformers in localization of the origin of partial discharge. In this paper, the transformer winding is first modeled in a transient state by using RLC ladder network and multiconductor transmission line (MTL) models. The parameters of the two models were calculated by Ansoft Maxwell software, and the simulations were performed by Matlab software. Then, the PD pulses were applied to the models with different widths of pulses. With regard to the fact that the signals received after the application of PD had a variable frequency nature over time, and based on the wavelet transform and signal energy, a new method was presented for the localization of PD. Ultimately; the mentioned method was implemented on a 20 kV winding distribution transformer. Then, the performances of the models used in this paper, including RLC and MTL models, were compared in different frequency bands for the correct distinction of partial discharge location.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 춘계학술대회
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• pp.2088-2093
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• 2004

Harmful elements from the exhaust gases are caused by incomplete combustion of mixture inside the engine cylinder and this abnormal combustion like misfire or partial burning is the direct cause of the air pollution and engine performance degradation. In this study, I obtain the shapes of spark, voltage and current generated when changing the experimental parameters such as grounded electrode shapes, electrode gap and the material of center electrodes. After that, I produce ignition energy by using the voltage and current and classify ignition energy into capacitive discharge energy and inductive discharge energy.

• KEPCO Journal on Electric Power and Energy
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• 제8권2호
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• pp.119-126
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• 2022

A growing number of gas-insulated transformers in underground power substations in urban areas are approaching 20 years of operation, the time when failures begin to occur. It is thus essential to prevent failure through accurate condition diagnosis of the given facility. Various solid insulation materials exist inside of the transformers, and the generated decomposition gas may differ for each gas-insulated equipment. In this study, a simulation system was designed to analyze the deterioration characteristics of SF₆ decomposition gas and insulation materials under the conditions of partial discharge and thermal fault for diagnosis of gas-insulated transformers. Degradation characteristics of the insulation materials was determined using an automatic viscometer and FT-IR. The analysis results showed that the pattern of decomposition gas generation under partial discharge and thermal fault was different. In particular, acetaldehyde was detected under a thermal fault in all types of insulation, but not under partial discharge or an arc condition. In addition, in the case of insulation materials, deterioration of the insulation itself rapidly progressed as the experimental temperature increased. It was confirmed that it was possible to diagnose the internal discharge or thermal fault occurrence of the transformer through the ratio and type of decomposition gas generated in the gas-insulated transformer.

• 한국전기전자재료학회논문지
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• 제31권4호
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• pp.255-260
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• 2018

In recent years, increasing electricity use has led to considerable interest in green energy. In order to effectively supply, cut off, and operate an electric power system, many electric power facilities such as gas insulation switch (GIS), cable, and large substation facilities with higher densities are being developed to meet demand. However, because of the increased use of aging electric power facilities, safety problems are emerging. Electromagnetic wave and leakage current detection are mainly used as sensing methods to detect live-line partial discharges. Although electromagnetic sensors are excellent at providing an initial diagnosis and very reliable, it is difficult to precisely determine the fault point, while leakage current sensors require a connection to the ground line and are very vulnerable to line noise. The partial discharge characteristic in particular is accompanied by statistical irregularity, and it has been reported that proper statistical processing of data is very important. Therefore, in this paper, we present the results of analyzing ${\Phi}-q-n$ cluster distributions of partial discharge characteristics by using K-means clustering to develop an expert partial discharge diagnosis system generated in a GIS facility.

• Journal of Electrical Engineering and Technology
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• 제11권1호
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• pp.192-199
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• 2016

With changes in insulated defects, the environment, and so on, new partial discharge (PD) data are highly different from the original samples. It leads to a decrease in on-line recognition rate. The UHF signal and pulse current signal of four kinds of typical artificial defect models in gas insulated switchgear (GIS) are obtained simultaneously by experiment. The relationship map of ultra-high frequency (UHF) cumulative energy and its corresponding apparent discharge of four kinds of typical artificial defect models are plotted. UHF cumulative energy and its corresponding apparent discharge are used as inputs. The support vector machine (SVM) incremental method is constructed. Examples show that the PD SVM incremental method based on simulated annealing (SA) effectively speeds up the data update rate and improves the adaptability of the classifier compared with the original method, in that the total sample is constituted by the old and new data. The PD SVM incremental method is a better pattern recognition technology for PD on-line monitoring.