Effect of connected burden on CT performance

[skm]

We have specified CTs with 40VA rated burden for both metering as well as protection cores, whereas the connected load is less than 10VA.

My question is whether this will have any adverse effect on the connected relays / meters? Any precaution to be taken while specifying ISF / ALF?

Regards,

SKM

 

[buzzp]

There is no issue with your burdens on these transformers if you have calculated it throughout the range of current (fault levels for your protective relaying)to make sure your relaying sees the full current. You must be using some old electro-mechanical relays to have these high burdens?
Not sure what this means: "Any precaution to be taken while specifying ISF / ALF?".

 

[RalphChristie]

I assume you are in the IEC-world:
ISF - instrument security factor.
ALF - accuracy limit factor.

Check the replies of scottf in thread238-113320:
Protection - last paragraph of his first reply.
Metering - His reply to stevenal.