Special Studies

Very Fast Transient Over Voltage Study

  • EMTP Software is used for simulation of VFTO Studies in GIS Substations
  • Studies shall be based on IEEE 1313.2, IEC 60071
  • Objective of the study is estimate the size of VFTO and its front time and relevant effect on the substation equipment
  • Detailed Modelling of GIS shall be done in EMTP to obtain accurate results
  • Opening / Closing of a DS,  Operation of a CB, the occurrence of a line-to-ground fault or the closing of an earthing switch are causes of VFTO
  • The VFTO analysis is performed with various GIS Dis-connector operations in accordance with the methodology and guidelines as per CIGRE WG D1.03-TB 519 and the results are validated by assessing over voltages at various surge impedance transition points in the system