Understanding Line Distance protection (21)

End-to-end testing can appear to be a daunting task. However, any relay tester can perform successful end-to-end tests with a basic a basic understanding of transmission line protection (or 21 impedance protection) along and some preparation before the testing is scheduled to begin.

The second video in our end-to-end testing series continues our introduction to transmission line protection (also called impedance protection, 21-element protection, or line distance protection). We perform a series of end-to-end tests on a normal transmission line with standard line distance protection and compare the results to a POTT scheme to see how standard distance protection is different than communication-assisted tripping schemes.

You can play with these animations at our website http://relaytraining.com/. Each of the most commonly applied protection schemes have their own animations and they can be found at http://relaytraining.com/tag/end-to-e....

The standard line distance animation can be found at http://relaytraining.com/distance-pro....

The POTT scheme animation can be found at http://relaytraining.com/pott-animation/.

This video expands on the descriptions found in The Relay Testing Handbook: Principles and Practice, Testing Line Distance Protective Relays (21), and End-to-End Testing. You can order any of these books in print or as digital pdf downloads at our store (http://relaytraining.com/product-cate....