The excitation of UHF signals by partial discharges in GIS

Judd, M.D.; Farish, O.; Hampton, B.F.

doi:10.1109/94.486773

Cited by 326 publications

(130 citation statements)

References 13 publications

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“…Figure 5 shows typical injected current signal generated due to partial discharges generated during tree propagation. It is well established that the rise time and fall time of the injected current pulse formed due to partial discharge signal in the SF 6 insulation medium are of few nanoseconds radiating UHF signals [6]. Figure 6 (i) and (ii) shows typical time domain UHF signal generated due to partial discharge formed owing to tree inception and propagation under AC voltages and the corresponding FFT analysis of the time domain signal respectively.…”

Section: Analysis Of Uhf Signal Generated During Tree Growthmentioning

confidence: 99%

“…These pre-breakdown channels emanated from the defect site in the insulation structure resemble branches of a tree and, hence, the name "treeing" is given to the damage process and since such an occurrence is purely due to electrical stress the mechanism is termed as "Electrical Treeing" [2][3][4][5]. In general, the partial discharge injected current pulses involve rise and fall-times of about 1 ns or less, exciting signals in the UHF range of 300-3000 MHz [6].…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Understanding Electrical Treeing Phenomena in XLPE Cable Insulation Adopting UHF Technique

Sarathi¹,

Nandini²,

Danikas³

2011

Journal of Electrical Engineering

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A major cause for failure of underground cables is due to formation of electrical trees in the cable insulation. A variety of tree structure can form from a defect site in cable insulation viz bush-type trees, tree-like trees, fibrillar type trees, intrinsic type, depending on the applied voltage. Weibull studies indicate that a higher applied voltage enhances the rate of tree propagation thereby reducing the life of cable insulation. Measurements of injected current during tree propagation indicates that the rise time and fall time of the signal is of few nano seconds. In the present study, an attempt has been made to identify the partial discharges caused due to inception and propagation of electrical trees adopting UHF technique. It is realized that UHF signal generated during tree growth have signal bandwidth in the range of 0.5-2.0 GHz. The formation of streamer type discharge and Townsend type discharges during tree inception and propagation alters the shape of the tree formed. The UHF signal generated due to partial discharges formed during tree growth were analyzed adopting Ternary plot, which can allow one to classify the shape of tree structure formed.

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Section: Analysis Of Uhf Signal Generated During Tree Growthmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Understanding Electrical Treeing Phenomena in XLPE Cable Insulation Adopting UHF Technique

Sarathi¹,

Nandini²,

Danikas³

2011

Journal of Electrical Engineering

View full text Add to dashboard Cite

show abstract

“…3, a series arc occurs at an electrical junction in series with a load and is caused by an incomplete connection as the result of corrosion or vibration. The current flowing is much less than that of a parallel arc, but can causes line-to-ground faults or short circuits by oxidizing and thermally degrading the surrounding insulation materials [11][12][13][14]. …”

Section: Series Arc Dischargementioning

confidence: 99%

Frequency Spectrum Analysis of Electromagnetic Waves Radiated by Electric Discharges

Park¹,

Kil²,

Cheon³

et al. 2012

Journal of Electrical Engineering and Technology

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-In this paper, we analyzed the frequency spectrum of the electromagnetic waves radiated by an electric discharge as a basic study to develop an on-line diagnostic technique for power equipment installed inside closed-switchboards. In order to simulate local and series arc discharges caused by an electric field concentration and poor connections, three types of electrode systems were fabricated, consisting of needle and plane electrodes and an arc generator meeting the specifications of UL 1699. The experiment was carried out in an electromagnetic anechoic chamber, and the measurement system consisted of a PD free transformer, a loop antenna with a frequency bandwidth of 150 kHz-30 MHz, an ultra log periodic antenna with a frequency bandwidth of 30 MHz-2 GHz, and an EMI test receiver with a frequency bandwidth of 3 Hz-3 GHz. According to the experimental results, the frequency spectra of the electrical discharges were widely distributed across a range of 150 kHz-400 MHz, depending on the defects, while commonly found between 150 kHz and 10 MHz. Therefore, considering the ambient noise and antenna characteristics, the best frequency bandwidth for a measurement system to monitor abnormal conditions by detecting electromagnetic waves in closedswitchboards is 150 kHz-10 MHz.

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“…However, the live diagnosis depending on the classic method, such as existing infrared cameras and leakage current measurement method in the case of ultra high voltage switchgear, is not effective for the prevention of power outage accidents, because the switchgear internal structure is complex, and it is difficult to determine the occurrence of partial discharge [3]. As a live-diagnosis technique of GIS, UHF technology was applied to the switchboard, and the possibility of application studied [4,5]. The technology by using UHF sensors is simply measured, and the interpretation of diagnostic results is an easy technique, as waveform analysis is standardized by the result of numerous studies.…”

Section: Department Of Car Mechatronics Sahmyook University Seoul 1mentioning

confidence: 99%

Partial Discharge Detection of High Voltage Switchgear Using a Ultra High Frequency Sensor

Shin

Lee

Hong³

2013

Transactions on Electrical and Electronic Materials

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Partial discharge diagnosis techniques using ultra high frequencies do not affect load movement, because there is no interruption of power. Consequently, these techniques are popular among the prevention diagnosis methods. For the first time, this measurement technique has been applied to the GIS, and has been tested by applying an extra high voltage switchboard. This particular technique makes it easy to measure in the live state, and is not affected by the noise generated by analyzing the causes of faults ? thereby making risk analysis possible. It is reported that the analysis data and the evaluation of the risk level are improved, especially for poor location, and that the measurement of Ultra high frequency (UHF) partial discharge of the real live wire in industrial switchgear is spectacular. Partial discharge diagnosis techniques by using the Ultra High Frequency sensor have been recently highlighted, and it is verified by applying them to the GIS. This has become one of the new and various power equipment techniques. Diagnosis using a UHF sensor is easy to measure, and waveform analysis is already standardized, due to numerous past case experiments. This technique is currently active in research and development, and commercialization is becoming a reality. Another aspect of this technique is that it can determine the occurrences and types of partial discharge, by the application diagnosis for live wire of ultra high voltage switchgear. Measured data by using the UHF partial discharge techniques for ultra high voltage switchgear was obtained from 200 places in Gumi, Yeosu, Taiwan and China's semiconductor plants, and also the partial discharge signals at 15 other places were found. It was confirmed that the partial discharge signal was destroyed by improving the work of junction bolt tightening check, and the cable head reinforcement insulation at 8 places with a possibility for preventing the interruption of service. Also, it was confirmed that the UHF partial discharge measurement techniques are also a prevention diagnosis method in actual industrial sites. The measured field data and the usage of the research for risk assessment techniques of the live wire status of power equipment make a valuable database for future improvements.

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The excitation of UHF signals by partial discharges in GIS

Cited by 326 publications

References 13 publications

Understanding Electrical Treeing Phenomena in XLPE Cable Insulation Adopting UHF Technique

Understanding Electrical Treeing Phenomena in XLPE Cable Insulation Adopting UHF Technique

Frequency Spectrum Analysis of Electromagnetic Waves Radiated by Electric Discharges

Partial Discharge Detection of High Voltage Switchgear Using a Ultra High Frequency Sensor

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