Propagation properties of electromagnetic wave through T-branch in GIS

Yoshimura, Manabu; Muto, Hirotaka; Nishida, C.; Kamei, Mitsuhito; Okabe, Shigemitsu; Kaneko, Shuhei

doi:10.1109/tdei.2007.344610

Cited by 36 publications

(13 citation statements)

References 8 publications

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“…The FDS between point 9 and 8 caused 4 dB of attenuation. When the signals propagated through Lshaped structures, the attenuation would be caused not only by the reflection but also the mode transformation between TEM mode and high order modes such as TE11 [13]. …”

Section: Metallic Protrusion At Locationmentioning

confidence: 99%

“…The PD source excites various modes of EM signals, the attenuation properties of which differs greatly [11]. The travelling of EM waves in GIS would encounter multiple reflection and mode transformations, which result in complicated processes [12][13][14][15]. Some research tasks have been done by both simulation and experiment tests in time domain through typical GIS structures such as basin-type insulators, L-shaped and T-shaped branches [16][17][18][19].…”

Section: Introductionmentioning

confidence: 99%

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Investigation of frequency characteristics of typical PD and the propagation properties in GIS

Gao

Zhao

Ding³

et al. 2015

IEEE Trans. Dielect. Electr. Insul.

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The secure operation of Gas Insulated Switchgear (GIS) is crucial for the bulk power systems, since the failure of GIS apparatus would cause severe interruption of power transforming and power supply at substations. Therefore, the monitoring and maintenance schemes of GIS devices have gradually taken the reliability-based indices into account, of which Partial Discharge (PD) levels in online monitoring are of substantial significance because PD serves as a major cause of insulation break-down. Ultra High Frequency (UHF) method is becoming widely adopted as the major inspection approach for PD in GIS. This paper presents the experiment-based results of the frequency characteristics of UHF signals caused by PD in typical defects using entire GIS operating system platforms. Specifically, the results covered the propagation attenuation of the UHF signals with peak to peak value and cumulative energy through typical structures, including basin-type insulators, Lshaped branch, isolating switches, current transformers, etc. The results serve as substantial criteria for optimal band width selection for high frequency detection, and as notable concerns to improve the sensitivity of UHF detection and the efficiency of online monitoring by effectively locating the external sensors for PD UHF detection.

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Section: Metallic Protrusion At Locationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Investigation of frequency characteristics of typical PD and the propagation properties in GIS

Gao

Zhao

Ding³

et al. 2015

IEEE Trans. Dielect. Electr. Insul.

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“…For the purpose of this article, radio wave refers to ultrashort wave and microwave with wide frequency domain and large information capacity potential, including public security 350MHz trunking communication network business and other public radio communication business. As the effect of ionosphere and stratosphere can be neglected for transmission of ultra-short wave and microwave, they will be directly deemed as vacuum, only secondary effect of ionosphere shall be taken into account sometimes at low frequency of ultra-short wave [8][9] . Main factors affecting ultra-short wave and microwave are ground surface object (landform, ground cover and especially ground surface building) and troposphere atmosphere above ground surface.…”

Section: Analysis Of Transmission Characteristic Of Radio Wavementioning

confidence: 99%

Design and Algorithm Study of Propagation Model in Fire Network

Yu-Feng

Sui

Qingbo

2014

2014 Fifth International Conference on Intelligent Systems Design and Engineering Applications

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In order to solve the fire command network communication problems not be guaranteed when fire forces implement fire rescue in a building, fire command network radio propagation model is designed and algorithm is investigated. First, the research is conducted from the firefighting and rescue emergency communication security status and characteristics of building fire, introduced the ITU-R indoor propagation model and Keenan-motley indoor propagation model. Then, using different frequencies experimental statistics of radio waves, we got the attenuation model results of interior building penetration. Finally, we established the attenuation model for the building penetration and wave field strength and level calculation. Several experimental results show that for the same building, using the frequency of 2.4GHz, 17dBm transmit power of the base station, we deploy single point and multi-point base stations to achieve signal coverage inside building, the measurement results which is obtained from spectrum analyzer shows that reception field strength of the signal can be achieved 97%9 9% at several predetermined monitoring. It can satisfy the communication support requirements of fire forces rescue.Keywords-fire and rescue；；communication security ；radio wave；transmission model ;

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“…Firstly, with regard to the PD phenomenon, Section 2 presents the detailed observation results of the PD current of the discharge in gas up to a high frequency band exceeding 10 GHz [15], as well as the study results of the insulation characteristics where micro-defects are present inside the epoxy insulator [16], the detectability of the UHF method with respect to the length of harmful particles inside GIS [17], and both experimental and numerical approaches on propagation phenomena of PD signal in GIS [18]. Subsequently, with regard to further refinement of the diagnostic technique and the calibration and verification method, Section 3 describes a new less uncertain and inexpensive UHF sensor calibration system using a conical antenna [19,20] and a more advanced UHF diagnostic technology whereby the influence of the shape and structures of GIS on PD signal propagation is taken into consideration [21,22], as well as a UHF measurement system sensitivity verification method on the site using a network analyzer [23] to substitute the CIGRE method [13], and the novel technique for PD and breakdown investigation based on current pulse waveform analysis [24].…”

Section: Introductionmentioning

confidence: 99%

New aspects of UHF PD diagnostics on gas-insulated systems

Okabe

Ueta

Hama

et al. 2014

IEEE Trans. Dielect. Electr. Insul.

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Gas insulated switchgears (GIS) have been increasingly introduced as main substationequipment since the late 1960s thanks to their high reliability, safety, and compactness. The UHF method to diagnose partial discharge (PD) is broadly employed in the field as an advanced insulation diagnostic technology. There are three primary factors related to the PD signal detection characteristics using this UHF method; namely the frequency spectrum of the PD signal itself inside GIS, the propagation characteristics of the PD signal inside the GIS tank, and the detection characteristics of the sensor measuring the PD signal. Accordingly, to further improvement of the diagnostic technique based on the UHF method, the PD phenomenon itself and its propagation characteristics should be clarified and the measurement system refined. From these perspectives, the present study reviewed the recent and latest findings concerning the PD phenomenon and its propagation characteristics inside GIS as well as the PD measurement system verification methods and diagnostic technologies, and summarized typical examples. Firstly, with regard to the PD phenomenon, measurement up to the high frequency band exceeding 10 GHz (even 30 GHz) clarified that the rise time of the PD current waveform is several tens of picoseconds, shorter than previously known. In the case of PD in micro-defects inside the epoxy insulator, however, the rise time is relatively long, in the order of nanoseconds, and a crack is the most critical defect. Subsequently, with regard to UHF PD diagnostics/monitoring technology, a novel technique using PD current waveform characteristics has been developed, and a more advanced PD diagnostic algorithm has been established by clarifying the influence of the shape and GIS internal structures on the electromagnetic wave propagation characteristics. Less uncertain and simplified calibration and verification technologies are also proposed both for a single UHF sensor and the entire UHF measurement system. These new technologies and further advanced studies in future are expected to make the UHF method more convenient and sophisticated.

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Propagation properties of electromagnetic wave through T-branch in GIS

Cited by 36 publications

References 8 publications

Investigation of frequency characteristics of typical PD and the propagation properties in GIS

Investigation of frequency characteristics of typical PD and the propagation properties in GIS

Design and Algorithm Study of Propagation Model in Fire Network

New aspects of UHF PD diagnostics on gas-insulated systems

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