GE Multilin has published a new white paper titled “CT Saturation in Industrial Applications - Analysis and Guidelines”. The paper provides a detailed analysis showing that, given typically applied settings on GE Multilin relays, instantaneous overcurrent functions operate dependably, even in extreme cases of very high short-circuit currents, and severely saturated low-ratio CTs.
It must be emphasized that there is a dramatic difference between relays using Fourier-like approach (cosine and sine filter), and relays based on true RMS value. The latter [used by GE Multilin] behave considerably better . . .
This paper: |
Explains and analyzes in detail the underlying mechanism of CT saturation.
Presents easy to grasp graphical methods, for quick evaluation of an application.
Analyzes several GE Multilin relays in response to heavily saturated CTs.
Provides alternative solutions for excessive applications |
Using this methodology, users of GE Multilin’s relays can apply them safely and confidently in applications where fault currents exceed rated currents by hundreds of times, even if low-ratio CTs have been used.
Download your copy of the paper 
Publication # GET-8502
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