Can You Predict What Happens in a Permissive Over-Reaching Transfer Trip (POTT) Scheme?

The Relay Testing Handbook: End-to-End Testing covers the most common Communication-Assisted Protection Schemes including the Permissive Over-Reaching Transfer Trip (POTT) Scheme. This bonus animation shows the steps involved for a POTT trip.

End-to-end testers should understand how this scheme operates before they test it and this animation was created to help relay testers understand distance relay principles.

Click on the following image to open an animation to see if you can accurately predict what will happen at different fault locations with a Permissive Over-Reaching Transfer Trip (POTT) Scheme. Press “What happens Next” to move through the animation.  Press “Move the Fault” to change the fault location.

Permissive Over-Reaching Transfer Trip (POTT) schemes have an inherent weakness due to their over-reaching nature.  This animation demonstrates a worst case scenario when using a POTT scheme during a sudden reversal.

Can you spot the problem?

Click on the following image to open an animation to see if you can accurately predict what will happen at different fault locations with a Permissive Over-Reaching Transfer Trip (POTT) Scheme. Press “What happens Next” to move through the animation.  Press “Move the Fault” to change the fault location.

You can watch this animation in action here: