Title :
Influence of VFT on Shell-Type Transformer
Author :
Fujita, Shigeto ; Shibuya, Yoshikazu ; Ishii, Masaru
Author_Institution :
Power Device Works, Mitsubishi Electr. Corp., Fukuoka
Abstract :
When a disconnecting switch in a gas insulated switchgear (GIS) operates, a high frequency oscillating surge called very fast transient (VFT) is generated. The VFT may set off overvoltage in a transformer winding. In the paper the authors evaluate the influence of VFT on a shell-type transformer. To simulate waveforms of VFT invading a transformer, a simple equivalent circuit for a shell-type transformer in a high frequency range is derived experimentally. Using this model the overvoltage waveforms are analyzed for various configurations of GIS. Then, the influence of VFT on a 500 kV shell-type transformer winding is investigated. The results lead to a conclusion that VFT does not threaten the reliability of insulation of the transformer winding
Keywords :
equivalent circuits; gas insulated switchgear; overvoltage; power transformer insulation; power transformers; reliability; transformer windings; transients; 500 kV; GIS; disconnecting switch; equivalent circuit; gas insulated switchgear; high frequency oscillating surge; insulation reliability; overvoltage; shell-type transformer; transformer winding; very fast transient; Circuit simulation; Frequency; Gas insulation; Geographic Information Systems; Power transformer insulation; Surges; Switches; Switchgear; Voltage control; Windings; Gas-insulated switchgear (GIS); transformer; very fast transient; voltage oscillation;
Journal_Title :
Power Delivery, IEEE Transactions on
DOI :
10.1109/TPWRD.2006.881430
