Suppression Of Very Fast Transient Over Voltages Across Insulating Flange Of UHV GIS

Vol.5 No.4

Year: 2012

Issue: Apr-Jun

Title: Suppression Of Very Fast Transient Over Voltages Across Insulating Flange Of UHV GIS  

Author Name: A. Raghu Ram, Jinka Amarnath , Dr.Kamakshaiah

Synopsis:   

In gas insulated substations (GIS), very fast transient over voltages (VFTO) are generated due to disconnector switching operations, disconnector switches (DS) are primarily used to isolate the       operating sectioning of HV insulation from each other as safety measure, vary fast transient over voltage(VFTO)  at  an  insulating  flange   are generated due to propagation of VFTOs on the conductor of a gas bus in GIS. Generation of VFTOs cases sparkovers across the insulating flange  of  high  pressure  oil  filled  cable/GIS interface. The ionized  path formed by spark over creates  low  impedance  path  for power frequency  fault  current  due  to  disconnector switching, resulting in flange damaged  with serious  consequences. This  paper  deals  the generation  of  VFTOs  across  the  insulating flange   and   suppressions   of   VFTOs   with shunting bars, capacitors across the flange for the  providing  potential  have  been  analyzed and reported in MATLAB 7.0.