Results 141 to 150 of about 452 (193)
Study on time-frequency analysis method of very fast transient overvoltage
The operation of the disconnector in the gas insulated substation (GIS) may produce very fast transient overvoltage (VFTO), which has the characteristics of short rise time, short duration, high amplitude and rich frequency components. VFTO can cause damage to GIS and secondary equipment, and the frequency components contained in the VFTO can cause ...
Shiming Liu
exaly +3 more sources
Suppressing resonance in transformer winding under very fast transient overvoltage
This paper presents a new method for suppressing internal resonance in power transformers connected to gas insulated substation (GIS) due to very fast transient overvoltage (VFTO) in the GIS. Internal resonance within the transformer windings will take place if one of VFTO frequencies matches with the power transformer natural frequency.
Mehdi Babaei +2 more
openaire +2 more sources
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Influence of the Switching Speed of the Disconnector on Very Fast Transient Overvoltage
IEEE Transactions on Power Delivery, 2013During the switching of disconnectors in gas-insulated switchgear (GIS), repeated strikes occur in the contact gap and lead to very fast transient overvoltage (VFTO). Severe VFTO may bring damage to transformers and other equipment. The switching speed of the disconnector is one of the important factors which influences VFTO.
Chen Weijiang, Xiang Zutao
exaly +2 more sources
Measurement study of very fast transient overvoltage in GIS
In power system, pulse voltage is measured by both the circuit and the electric field. The special measure of VFTO is determined by non-alterable equipments of GIS. In this paper, external transient voltage is measured by electric spherical probe which means it is not necessary to access any equipments to the system.
null Zhang Zhilongzhang +5 more
openaire +2 more sources
Numerical analysis of very fast transient overvoltage in GIS
Very fast transient over voltage (VFTO) is a kind of phenomenon which commonly occurs in gas insulated switchgear(GIS), and is also receiving more and more attention since it may endanger GIS internal insulation and secondary equipment. For this reason, combining with the VFTO phenomenon in GIS, this paper completed the numerical simulation calculation
null Dianchun Zheng +3 more
openaire +2 more sources
Very Fast Transient Overvoltage of UHVAC System
Compared with 500 kV EHV GIS substation, 1000 kV UHV GIS/HGIS substation has different characteristics in terms of switchgear, system structure, insulation margin, requirements on safety and stability and importance. And the hazardness of very fast transient overvoltage (VFTO) on UHV GIS is much heavier than that in 500 kV power system.
Yang Li, Guoming Ma, Hao Zhou
openaire +2 more sources
Very Fast Transient Overvoltage Measurement With Dielectric Window
IEEE Transactions on Power Delivery, 2014The method of using the electrode inserted into gas-insulated switchgear (GIS) to form a capacitor sensor has the best bandwidth to measure the very fast transient overvoltage. However, the power in the GIS conductor has to be cut off during the repair and replacement of the sensor.
Guoming Ma, Cheng-Rong Li
exaly +2 more sources
Very fast transient overvoltage analysis for 400KV GIS
The very fast transient overvoltage (VFTO) produced during isolator switching operation in EHV GIS substations could impose a potential risk of insulation breakdown in the equipment connected directly to the GIS. A quantitative assessment of the expected VFTO against the VFTO withstand capability of the concerned EHV equipment is necessary for power ...
H.K. Wong, null Shihe Chen
openaire +2 more sources
Influence of switching properties of the disconnector on very fast transient overvoltage
During switching operations of disconnectors in gas insulated switchgear (GIS), very fast transient overvoltage (VFTO) is generated due to multiple strikes across the switching contact. Switching properties, such as switching speed and trapped charge, have some impacts on VFTO behavior.
null Huamao Zhan +3 more
openaire +2 more sources

