Forum » General Discussion » Disadvantage of connecting a metering relay in series with protection relay in one CT core
Topics: Disadvantage of connecting a metering relay in series with protection relay in one CT core on General Discussion
#1
Start by
Mihla Khumalo
12-13-2013 12:59 AM
Disadvantage of connecting a metering relay in series with protection relay in one CT core
Morning fellow engineers! Please help; is there a serious disadvantage of connecting a metering relay in series with protection relay in one CT core?Regards
12-13-2013 03:12 AM
Top #2
Alan Maltz
12-13-2013 03:12 AM
Mihla,
It depends upon how you wish to define serious:
Is redundancy important to you?
Are you concerned about increasing the burden on your CT?
Do you care if you introduce additional points of failure into your relaying circuit?
Do you mind if your technicians have to recalibrate/re-certify the relaying system because it was disturbed to add the metering circuit?
If you answered "Yes" to any of these questions (and there are others) then you should weigh the risks/benefits carefully.
On the other hand if you are facing an emergency situation then it will work as long as you are not exceeding the CT burden/relaying accuracy with the additional equipment, AND your protection engineer gives it his blessing.
