LTPU on relays?

[budhiman]

Hello Everyone,

I have a question on providing settings for overcurrent relays. When providing settings for 51 element is it required to keep in mind CT saturation. For example - A 50:5 CT is connected to a relay which has a pickup setting available from 0.5 -20 x CTR. Can the pick up be set to 20?

 

[FreddyNurk]

There isn't enough provided information to answer that question, although the ANSI method of designating CTs may be different.

Details of:
[ul]
[li]CT Specification (e.g. 50P20F20 or 5P20 20VA)[/li]
[li]Connected Burden[/li]
[li]Maximum expected primary current[/li]
[/ul]
Would need to be considered before being able to advise on whether or not the CT would saturate before the pickup point is reached, at least for an IEC application.