Transformer Differential Protection CT Accuracy Class Mismatch
Transformer Differential Protection CT Accuracy Class Mismatch
(OP)
Hello All,
When implementing a differential protection for a transformer is there a problem if the accuracy class for the transformer primary CT is class C400 and the secondary CT at the switchgear is C200?
When implementing a differential protection for a transformer is there a problem if the accuracy class for the transformer primary CT is class C400 and the secondary CT at the switchgear is C200?





RE: Transformer Differential Protection CT Accuracy Class Mismatch
In modern relays you can adjust the differential characteristic slope settings to help account for this, at the cost of raising lowering the sensitivity of the element. The calculations are relay specific and depend on how each relay manufacturer calculates the restraint current.