Understanding phase rotation is vital when connecting two systems together because the results can be catastrophic if someone doesn’t understand how to interpret phase rotation drawings. You would think something as important as phase rotation would have consistent terms across the entire industry. Unfortunately, you’d be wrong. Let’s start with
Here is the latest video describing the Permissive Under-Reaching Transfer Trip Communication-Assisted Trip Schemes used in modern distance protection. You can follow along with this animation via the Can You Predict What Happens in a Permissive Under-Reaching Transfer Trip (PUTT) Scheme? post found under the Testing handbooks / Book Extras
A reader has requested some help for an upcoming project: I will be reviewing some relay testing that needs to performed shortly and I am trying to understand how the 27/47/59N (within a SEL 387E) relay function is being applied. The 387E provides the 87T function for the 115KV to
I’ve noticed that many students don’t seem to have experience with phase angle meters, and they can’t guess what a phase angle meter would measure in simple circuit. This knowledge is CRITICAL if you want to perform a protective relay meter test properly. Anyone can inject voltages and currents into
Chris will be at the 34th Annual Hands-On Relay School this year. Stop by the Suppliers Showcase on Tuesday evening to meet the author of The Relay Testing Handbook Series, or check out our collection of vintage protective relay books to see how little the electrical industry has changed over
Sometimes the hardest part of relay testing is getting your laptop to talk to the relay or test-set. There are two primary communication methods: Serial Connections Serial communication is the most common path between devices because it came first. Luckily for you, the industry has pretty much standardized on DB-9 serial connection and
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