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Optimal Design of a Follow Current Disconnector for DC Arresters in Traction Vehicles
Guoming Wang,,김선재,Seo-Jun Park,Gyung-Suk Kil,Hong-Keun Ji 한국전기전자재료학회 2016 Transactions on Electrical and Electronic Material Vol.17 No.5
This paper dealt with the optimal design of a follow current disconnector for DC arresters used in electric tractionvehicles. The disconnector separates the ground lead from an arrester to prevent a line-to-ground fault of an agedarrester and should not affect the operation and function such as the reference and the clamping voltage of theconnected arrester. The designed disconnector is composed of a resistor, a spark gap, and a cartridge. The resultsshowed that the sparkover voltage increased with the gap distance whereas the reference voltage was almost the sameas that without the disconnector. The sparkover voltage was 3.95 kV when the gap distance was 0.5 mm. Regardlessof the gap distance, the reference and the clamping voltage of the assembled disconnector with an arrester weremeasured to be the same as those of the arrester alone.
Guoming Wang,김우현,공정배,길경석,Hong-Keun Ji 한국전기전자재료학회 2018 Transactions on Electrical and Electronic Material Vol.19 No.3
This paper dealt with the application of transient earth voltage (TEV) sensors for the online measurement and analysis ofpartial discharge (PD) in medium-voltage switchboards. To simulate the typical insulation defects in the switchboards, fourtypes of artifi cial electrode systems, including high-voltage protrusion, low-voltage protrusion, particle-on-conductor, andvoid inside cast-resin potential transformer were fabricated. A TEV sensor with a frequency range of 1–150 MHz and anon-inductive resistor were used to detect the PD-induced TEV signal and the PD voltage pulse, respectively. The frequencyspectrums of TEV signals were analyzed, and it was found that they had a mutual frequency range of 5–50 MHz. However,the amplitude of TEV signal was not proportional to the apparent charge specifi ed in IEC 60270, resulting the diffi culty ofquantifi cation of PD. The phase-resolved partial discharge patterns were acquired using the TEV sensor and the developedmeasuring algorithm, by which distinguishable patterns were obtained from diff erent defects.
Optimal Design of a Follow Current Disconnector for DC Arresters in Traction Vehicles
Wang, Guoming,Kim, Sun-Jae,Park, Seo-Jun,Kil, Gyung-Suk,Ji, Hong-Keun The Korean Institute of Electrical and Electronic 2016 Transactions on Electrical and Electronic Material Vol.17 No.5
This paper dealt with the optimal design of a follow current disconnector for DC arresters used in electric traction vehicles. The disconnector separates the ground lead from an arrester to prevent a line-to-ground fault of an aged arrester and should not affect the operation and function such as the reference and the clamping voltage of the connected arrester. The designed disconnector is composed of a resistor, a spark gap, and a cartridge. The results showed that the sparkover voltage increased with the gap distance whereas the reference voltage was almost the same as that without the disconnector. The sparkover voltage was 3.95 kV when the gap distance was 0.5 mm. Regardless of the gap distance, the reference and the clamping voltage of the assembled disconnector with an arrester were measured to be the same as those of the arrester alone.
Optimization of wavelet and thresholding for partial discharge detection under HVDC
Wang, Guoming,Kim, Sun-Jae,Kil, Gyung-Suk,Kim, Sung-Wook IEEE 2017 IEEE transactions on dielectrics and electrical in Vol.24 No.1
<P>With the rapid development of HVDC technology, the detection and analysis of partial discharge (PD) under HVDC are new challenges to ensure reliable operation of the related power apparatus. The wavelet technique has been proposed for analyzing PD pulses under HV AC and ultra- high frequency signal, but its application for PD under HVDC has not been discussed. This paper dealt with the selection of the optimal wavelet and thresholding for PD pulses in order to apply the wavelet technique to PD detection under HVDe. Four electrode systems, namely protrusion on conductor, protrusion on enclosure, free particle, and crack inside spacer were fabricated to simulate typical defects in a gas insulated switchgear. The detected PD pulses were decomposed by multiresolution analysis. The correlation coefficient and dynamic time warping methods were used to select the optimal wavelet. The optimal threshold and thresholding function were chosen from various combinations with the simulated pulses. The results revealed that processing PD pulses with the mother wavelet of bior2.6, automatic threshold, and intermediate thresholding function presented the best performance.</P>
Wang, Guoming,Kim, Woo-Hyun,Kong, Jeong-Bae,Kil, Gyung-Suk,Ji, Hong-Keun The Korean Institute of Electrical and Electronic 2018 Transactions on Electrical and Electronic Material Vol.19 No.3
This paper dealt with the application of transient earth voltage (TEV) sensors for the online measurement and analysis of partial discharge (PD) in medium-voltage switchboards. To simulate the typical insulation defects in the switchboards, four types of artificial electrode systems, including high-voltage protrusion, low-voltage protrusion, particle-on-conductor, and void inside cast-resin potential transformer were fabricated. A TEV sensor with a frequency range of 1-150 MHz and a non-inductive resistor were used to detect the PD-induced TEV signal and the PD voltage pulse, respectively. The frequency spectrums of TEV signals were analyzed, and it was found that they had a mutual frequency range of 5-50 MHz. However, the amplitude of TEV signal was not proportional to the apparent charge specified in IEC 60270, resulting the difficulty of quantification of PD. The phase-resolved partial discharge patterns were acquired using the TEV sensor and the developed measuring algorithm, by which distinguishable patterns were obtained from different defects.