This study presents the manner in which transient modeling concepts, which are fully analyzed in the referred standards, are implemented, for the purpose of evaluating the Transient Ground Potential Rise (TGPR). This is a phenomenon of 10–100kV voltages with up to 10μs duration on the grounded enclosure of Gas Insulated Substations (GIS), which may cause concern for personnel safety and problem...

This study presents the manner in which transient modeling concepts, which are fully analyzed in the referred standards, are implemented, for the purpose of evaluating the Transient Ground Potential Rise (TGPR). This is a phenomenon of 10–100kV voltages with up to 10µs duration on the grounded enclosure of Gas Insulated Substations (GIS), which may cause concern for personnel safety and pro...

Due to the opening or closing of circuit breakers and disconnect switches in Gas Insulated Substations (GIS), especially in the pumped storage power stations, Very Fast Transient Over-voltages (VFTO) are generated. This paper describes the 500 kV and 750 kV GIS. The variations of VFTO magnitudes at different points in 500 kV and 750 kV GIS during different switching operations have been calcula...

VFT (variable frequency transformer) has been recently used as an alternative to HVDC (high voltage direct current) to control power flow between asynchronous networks. VFT consumes less reactive power than a back-to-back HVDC system, provides faster initial transient recovery, and has better natural damping capability. VFT is simply a DFIM (doubly-fed induction machine) where the machine torqu...

The effect of disopyramide phosphate (DP) infusion (1 mg/Kg and 2 mg/Kg BW) on ventricular fibrillation threshold (VFT) was studied in anesthetized dogs. In the 1 mg/Kg group, the VFT increased 47% above the control level immediately after infusion. In the 2 mg/Kg group, a delayed increase in VFT was observed after the initial period and VFT was not correlated with the plasma concentration of D...

The electric power systems are interconnected for the economical and reliable operation of supply systems. An interconnection can be implemented through AC DC links. A variable frequency transformer (VFT) has emerged as an alternative asynchronous interconnection, like back-to-back HVDC Unlike links, VFT requires reduced reactive power, offers quicker incipient transient recovery, coherent damp...