Category Archives for Relay Testing Techniques

Use Sequence Components To Make Sure Your Relay Isn’t Disabled By Incorrect Phase Rotation

Did you know that a relay connected to, or set with, the incorrect phase rotation can disable its higher level functions? Did you know that the wrong phase rotation can make your relay testing worthless?

How to Perform an In-Service Protective Relay Meter Test

In-service protective relay meter tests are THE MOST important tests that should be performed on every digital relay. All of your offline relay testing is meaningless if: The CT/PT ratios are incorrect. The

How to Perform Dynamic Relay Testing on Digital Relays

If you’ve read anything about relay testing written in the last ten years or so, you’ll see a pattern; No-one is talking about the traditional pickup and timing tests most relay testers (and

Why Does My Open-Delta Connected Phasor Diagram Look Weird?

Meter tests on protected relays connected to open-delta connected PTs can be very confusing. I know I spent a LOT of time trying to figure out the values reported by my first open-delta connected relay

How To Communicate with a Test-Set or Relay

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

When I test induction disc relay type … Is the pickup value the value at which the disc starts rotating?

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

Testing Directional Overcurrent Relays

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

Finding the Direction in Directional Overcurrent Relays

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

Why did my Frequency Test in Cycles Fail?

We added a new YouTube video, Why did my Frequency Test in Cycles Fail?. This video describes how two different relays with identical settings can have different time test results when performing any frequency

Understanding Microprocessor Relay Logic – Microprocessor Relay Testing Plans

We have uploaded our fourth YouTube video, Understanding Microprocessor Relay Logic – Microprocessor Relay Testing Plans. (http://youtu.be/ijdSKozctNo) This video discusses how to turn the microprocessor

Understanding Microprocessor Relay Logic – Relay Digital Logic Schemes

We have uploaded our third YouTube video, Understanding Microprocessor Relay Logic – Relay Digital Logic Schemes. (http://youtu.be/do3EkEcb0eM) This video discusses the different relay digital

Testing Basler BE1-47N Negative Sequence Voltage Relays

Testing more complicated elements that use a percentage or ratio between values can be difficult if you cannot properly define all of the values in the equation. It doesn’t help that different

Good Videos to Help Understand Protective Relays

I’m reviewing information for the next book in The Relay Testing Handbook series and came across this Youtube channel. This is a dated, but excellent, video introduction to overcurrent protection (50/51)

SEL Test Procedure Negative-Sequence Volt-Pol Directional Overcurrent Element

I am writing to enquire about 67N test procedures, specifically Schweitzer relays. The Page 94 of the Relay Testing Handbook #C2 : Practical Relay Testing (50/51/67/59/27/81/87/21) by Chris Werstiuk says

Real World Problem With an SEL-300G Synch-Check

Here is a story from one of our Customers at Manta Test Systems: “I had to troubleshoot a Schweitzer SEL-300G relay yesterday that had the (25) Sync-Check element enabled, but wouldn’t assert the

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