You may find the simple grid model with two terminals and a power transformer, protected by a differential protection in the attachment of this FAQ.

Here, an emphasis is on the way the adapters had been set up, in order for the differential scheme to work. To learn more about setting up the adapters, please have a look at the following FAQ:

https://www.digsilent.de/en/faq-reader-powerfactory/why-is-my-transformer-differential-protection-tripping-non-selectively.html