Current Transformers designed for 50 Hz but operating at 60 Hz

[wubman]

Recently I attended a Factory Acceptance Test of Current Transformers for Substations, the tests were accidentally started at 60 Hz, but the CTs were designed for 50 Hz, when I saw the accuracy test results, they were almost the same, what would be the consequences in terms of accuracy and life span of the CTs under a permanent operation of at 60 Hz, considering that they were designed to operate at 50 Hz.
I would welcome some links regarding this issue

 

[randyman]

Dielectrically speaking, as long as the maximum system voltage the CT is rated is not exceeded, then there should be no problems.

For metering purposes, the differences in RCF and phase angle readings from 50Hz to 60Hz are typically negligible and well within the limits of uncertainty. If the CT, as in the IEC world, has an instrument security factor then that factor might be a bit higher at 60Hz, but other than that there should be no problems at all.

On the other hand, for protection purposes at 60Hz the same CT will yield ~20% more voltage and have slightly lower excitation loss.

This is from experience, but it is always best to get the manufacturer's blessings.