Capacitive Arc Model

Accurate estimation of VFTO in GIS substations


Switching of Bus-charging currents are common operations in HV substations normally performed by the disconnectors (DS), it consists on the switching operation of an AC voltage source from an unloaded section of busbar and it causes several dielectric breakdowns to occur across the gap during the switching process. These breakdowns produce the so called Very Fast Transient Overvoltages (VFTO) phenomena that travels towards all of the connected equipment. VFTO peak voltage is normally obtained by electromagnetic transient calculations before deciding wether or not mitigation systems are required to protect the disconnector and adjacent equipment. The accurate modelling of every element of the substation including the electric arc is key for a good estimation of VFTO.


Available license



  • Delivered as a turnkey solution
  • Easy to implement and easy to use
  • Compatible with open source software and any circuit simulation tool


  • UHV-AC Substations
  • Insulation Coordination
  • VFTO Studies
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