Distance Protection (21) has many names (Line Protection, Line Distance Protection, Impedance Protection) and is one of the more complicated elements used in protective relaying. The Relay Testing Handbook series explains Line Distance Protection.
This bonus animation was created to help relay testers understand distance relay principles.
See if you can accurately predict what will happen at different fault locations.
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.