MiCOM P122 Relay Question

[Elec81]

Hi,

I have a quick question regarding the MiCOM P122.

In the relay manual it states that the operation TIME tolerance for thresholds I>, I>> and I>>> is +/- 2% +30...50ms. Therefore, am I correct in thinking the NEGATIVE tolerance for a set curve is 2% of a set value. Also, that the POSITIVE tolerance for a set curve is 2% of the set value PLUS 50ms.

Many thanks in advance.

 

[RRaghunath]

I think 50ms gets added for the 2% error whether it is on positive or negative side.
For example, if set time delay is 500ms, the relay may operate in 440ms or 560ms or in between.

 

[ppedUK]

The +/-2% tolerance is applied to the Time/Current curve. The 30...50ms is the time taken for the trip output relay to energise in all cases when the the trip threshold has been reached.