The very fast transient overvoltage (VFTO) is characterized by steep wavefronts, high amplitude, and wide spectrum. These characteristics can lead to partial discharges or insulation breakdowns in potted insulators, which can lead to localized overhe...
Very fast transient overvoltages (VFTOs) from disconnector operations in gas-insulated switchgear (GIS) stress the sheath sectionalizing insulation at cable terminations, where a bypass sheath voltage limiter (BSVL) protects it. At these frequencies,...
The FDS (Frequency-domain Dielectric Spectroscopy) of oil-immersed insulation paper, and semi-conductive paper with different moisture content, has been measured. The data measured are fitted as a function of frequency and moisture content using the...
To thoroughly analyze the high-frequency and high-amplitude electromagnetic disturbances generated during disconnector operation, this paper proposes an equivalent modeling approach based on dynamic arc behavior. The model incorporates the resistance...
Disconnect switch and circuit breakers operations in gas insulated switchgear (GIS) systems may produce very fast transient overvoltage (VFTO). Detecting VFTO is the first step for researchers to reduce the damage to other equipment of the substation...
Operating overvoltage occurs when the pantograph or main breaker of an electric locomotive is operated, which is prone to causing insulation failure of high-voltage equipment. The HXD1 electric locomotive is taken as the research object in this paper...
To address the problem of winding turn-to-turn breakdown faults in 35 kV dry-type transformers in wind farms under overvoltage conditions, this paper establishes a simulation model based on the structural dimensions and material parameters of the tra...
When the electric locomotive pantograph is dropping, the interruption of pantograph catenary contact causes electromagnetic oscillation and arcing. The frequent arc burning that occurs due to charge accumulation results in the amplitude of overvoltag...
A High-Altitude Electromagnetic Pulse (HEMP) could induce very fast transient overvoltage (VFTO) with nanosecond level rise time and mega-volt amplitude, which severely threatens the electrical devices connected to the elevated transmission line. An...
The accurate identification of Very Fast Transient Overvoltage (VFTO) is the key of overvoltage control in modern smart grids. In order to accurately identify VFTO generated by the operation of a disconnector in Gas Insulated Substation (GIS), a VFTO...
Modelling for very fast transients (VFTs) requires good knowledge of the behaviour of gas insulated substation (GIS) components when subjected to high frequencies. Modelling usually takes the form of circuit-based insulation coordination type studies...
The insulation system’s dielectric of the electric motor is very often subjected to severe electrical stress generated by the high
Assessment of very fast transient overvoltage (VFTO) requires good knowledge of the behavior of gas-insulated substation when subjected to very high frequencies. The international standards and guidelines generically present only recommendations rega...
Very fast transient overvoltage (VFTO) generated by an operating disconnector is one of the main reasons for electromagnetic disturbance in gas-insulated switchgear (GIS) substations. Generally, the amplitude of VFTO can be used as one of the referen...
Gas insulated substations (GISs) are broadly used for transmission and distribution in electric power networks. Very fast transient overvoltage (VFTO) caused by SF6 discharge during switching operations in a GIS may threaten the insulation of electri...
Multiple restrikes during gas-insulated switchgear (GIS) disconnector operations generate very fast transient overvoltage and associated electromagnetic disturbance. Conventional circuit-based simulations can reproduce the temporal sequence of multip...
Very fast transient overvoltage (VFTO) is characterized by short wavefront time, high amplitude and wide frequency. VFTO poses a threat to the safe operation of power equipment. In order to suppress the harmful effects of VFTO transmission on power e...
The very fast transient overvoltage (VFTO) generated by the operation of disconnectors in gas-insulated switchgears (GIS) features a wide frequency band and a steep rising edge, posing a severe threat to the safe and stable operation of power grids....
At present, the detection of transformer winding deformation faults is carried out in an offline state, which requires the transformer to cooperate with the implementation of planned power outages, or it takes place after the sudden failure of the tr...