Transformer and generator time-overexcitation relay and protection assemblies
The inverse time tripping is settable with different characteristics in order to suit different types of power transformers. 10 different inverse and fixed time delay characteristics are selectable on the relay making it suitable for most transformer and generator overexcitation applications.
The relay includes one setting having the same inverse shape as the earlier RATUB relay and may therefor be used as a RATUB replacement. The different inverse V/Hz characteristics available are advantageous by providing better protection and utilization of the V/Hz capability of the protected object than fixed time delay V/Hz relay solutions.