The general setting range is approximately 0. 5 to 1 second to quickly clear ground faults. Overvoltage Protection Overvoltage protection is a critical component of grounding transformer protection . This guide focuses primarily on application of protective relays for the protection of power transformers, with an emphasis on the most prevalent protection schemes and transformers. In most cases the 110% NL limit is more restrictive than the FL limit and would be plotted on the coordination curve set unless the GSU impedance is < 7% or so (Zt at max GSU MVA rating). In some applications, the GSU LS voltage rating may be < the gen voltage rating to compensate for the voltage. LAY S TTIN LAY SETTIN of CT groups flication descriptions and setting guidelines sorted per function.
