This question was submitted via the Ask Chris form where you can ask me relay testing questions that I can hopefully answer. Creating test plans for digital relays is often difficult because you can have ten relays with identical model numbers that have completely different functionality. Conversely, ten induction disc relays of
In the previous post about Directional Overcurrent relay (67) testing (Finding the Direction in Directional Overcurrent Relays), we reviewed Directional Overcurrent protection from a system perspective to enhance the descriptions in The Relay Testing Handbook: Principles and Practice. We’ll be looking at Directional Overcurrent relays from a testing perspective in
A reader submitted a question through the Ask Chris form. I’ve expanded the original question from “what are the differences between relays, contactors and motor starters?” to “What is the difference between contactors, motor starters, relays and circuit breakers?” We’ll look at the history of electrical protection in this post
Situation after CT Primary Injection: New 230kv breaker Testing CT’s, 4000/5, by high current injection injecting 80 amps A phase to ground the secondary leads are shorted in a junction box A-B-C-N / additionally a voltage is connected to test instrument form test set The secondary readings are A = 0.096
A reader recently asked a question about the forward and reverse directions described in the Directional Overcurrent Relay section of The Relay Testing Handbook series. I used electro-mechanical directional relays as an example, which may have been a mistake. Let’s take another look at the Directional Overcurrent (67) element from a
SEL 321 OSB upper tests fine, lower is no-op but 51g comes in any ideas? I’m oversight on a project, test company is using a Doble 6150 w/ RTS, I’m not very familair with RTS sdg
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