25 - Full length Differential test

[@frasermason6014]

Just tested my first Siemens 7SR242 Duobias with an SMRT. The notes on single phase pickup factor are quite light on the PowerDB software but follow the guidance in the video and look at the relay manual, specifically the applications guide. If you look at the Siemens manual for the relay I mentioned, find the application guide for a Phase-Earth fault, and you will see that the current that reaches the differential element is not always the current you need to inject with your test gear. For instance, if you have a Yd interposing CT, 1A injected into the relay will actually only provide 1/root3 amps to the differential element - hence the pick-up factor needs to be set in the software to compensate for this and ensure that you get the green tick! ICT multiplier also affects the current that reaches the diff element vs the injected current, but in this case the injected current is lower. When you have ICT multipliers and Yd ICT connections you have to consider both in your pickup factor

[@frasermason6014]

If your interposing CT is connection is Yy then you don’t need the 1/root 3 scaling factor.

[@mr.biplob3795]

Pls also make tutorial distance relay of abb RED670 by this relay test kit.

[@mohitgupta1010]

What is single phase pickup factor?