Can You Predict What Happens in a Directional Comparison Unblocking (DCUB) Scheme?

The Relay Testing Handbook: End-to-End Testing covers the most common Communication-Assisted Protection Schemes including the Directional Comparison Unblocking (DCUB) Scheme. This bonus animation shows the steps involved for a DCUB 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.

See if you can accurately predict what will happen at different fault locations with a Directional Comparison Unblocking (DCUB) Scheme.

Click on the image below to start the animation. Press “What happens Next” to move through the animation.  Press “Move the Fault” to change the fault location.

Directional Comparison Unblocking scheme animation

About the Author Chris Werstiuk

Chris is an Electrical Engineering Technologist, a Journeyman Power System Electrician, and a Professional Engineer. He is also the Author of The Relay Testing Handbook series and founder of Valence Electrical Training Services. You can find out more about Chris here.

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