The relay uses a standard equation to set TAPn, based on settings entered for the particular winding (n denotes the winding number. ): The ratio TAPmax / TAPmin ≤ 7. 5This 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. Setting procedures are only discussed in a general nature in the material to follow. Protection selectivity is partly. Modern relays often have algorithms that enhance the security of elements that are otherwise susceptible to current transformer (CT) saturation. In this paper, we consider some of the similarities and differences between IEEE and IEC guidance on CT selection. These harm time during each cycle where the current magnitud unit (PU) on transfo acteristics that relate fault-current magnitude to. CT's transform line current down to a signal level that is acceptable to the relay. This signal level is typically 5A nominal. Multiple relays can use the same CT.
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