Coming Soon! The Relay Testing Handbook: Simplified Motor Protection Relay Testing

[one_half_first]The Relay Testing Handbook: Principles and Practice had been more than a decade in the making when it was published in 2012. It contained everything I knew about relay testing that could be included in a book format. The response from relay testers has been incredible and I’d like to thank everyone who supported us. We’re getting ready to release the next book in the series: Simplified Motor Protection Relay Testing.

This book applies the same straightforward approach from The Relay Testing Handbook: Principles and Practice to motor testing, including:[/one_half_first][one_half_last][/one_half_last]

1. Start by understanding the general operating characteristics of motors and their control schemes.
2. Review the documentation to make sure everything is designed to operate correctly.
3. Connect your test-set to the system to properly simulate the CTs, PTs, Inputs, and Outputs.
4. Review the generic motor testing principles you need to understand before attempting a motor protection test.
5. Perform an acceptance test to ensure the manufacturer sent a fully functioning relay.
6. Perform a commissioning test to make sure the relay will properly measure and protect the motor, including detailed descriptions and step-by-step instructions for the following elements:
   1. Meter Tests using Wye and Delta PTs
   2. Restart Block / Backspin
   3. Time Between Starts
   4. Starts per Hour
   5. Thermal Overload Trip
   6. Overload Alarm
   7. Thermal Capacity/Thermal Overload Alarm
   8. Mechanical Jam/Load Jam
   9. Acceleration Trip/Start Monitoring Trip
   10. Current Unbalance/Current Imbalance
   11. Single Phase Trip
   12. Short Circuit Trip/Phase Overcurrent (50P)
   13. Undercurrent/Load Loss
   14. Undervoltage/27P
   15. Overvoltage/59P
   16. Phase Reversal Trip
   17. Over/Under Frequency Protection/81D
   18. Power Factor Trip/55
   19. Reactive Power Trip/VART
   20. Underpower Trip/37PT
   21. Ground Fault Trip/Neutral Overcurrent (50N)
   22. Phase Differential Trip/Differential Trip (87M)
   23. RTD Temperature Testing

The first draft is written, the final layout is done (400+ pages!), and we’re just waiting for the last three rounds of editing before the final release.

If you want to learn how to test motor relays, this is the book for you.  But it is much, much more! It includes everything I’ve learned about relay testing since The Relay Testing Handbook: Principles and Practice, including step-by-step dynamic testing procedures that can be applied to any relay element with fixed-time delays. This is THE most comprehensive guide about motor protection relay testing AND dynamic relay testing. This book is a must read for anyone who wants to up their game from a button pusher to a true relay testing craftsman. Keep reading to learn more about dynamic testing…

What is Dynamic Testing and How Does it Apply to Motor Protection Relay Testing?

I’ve been lucky enough to train hundreds of students in a wide variety of organizations and industries since the previous book was published, which has significantly changed my perspective on relay testing. Meanwhile, the relay testing world has finally started to shift away from the traditional pickup and timing tests we used in the 20^th century, and is slowly headed toward modern test methods that include buzzwords like “system testing”, or “dynamic testing”. I covered these test methods briefly in The Relay Testing Handbook: Principles and Practice, but they should be the primary method for testing all relays.

“Dynamic testing” or “system testing” sounds great,  but what do they mean? I demonstrate these procedures in How to Test Protective Relays Online Seminar, but they aren’t well defined outside of relay conference papers and presentations. Traditional pickup and timing tests created for electro-mechanical relays make sense because you could bring a relay in, or out, of calibration when you performed your tests; therefore finding the exact pickup and timing results were vital to make sure the E-M relay was operating correctly. However, traditional tests aren’t well designed to find the failure points in a digital relay.  A dynamic test’s primary goal is to determine if the relay is programmed correctly, which means you do NOT reprogram the relay to get numbers for your test sheet.

A dynamic test:

1. Applies prefault conditions that mimic normal conditions.
2. Applies a fault that is just outside the relay’s tolerances that should not trip.
3. Applies normal conditions to make sure other elements don’t operate during the test.
4. Applies a fault that is just inside the relay tolerances that should trip.
5. Applies a post-fault condition that simulates what happens after the trip to help the relay tester evaluate the relay’s responses including:
   • Trip times
   • Which outputs operated
   • What messages are on the front panel of the relay to help operators understand what happened and make the right decision
   • What the relay recorded during the test to help troubleshooting personnel after the fault

Dynamic and system tests are more effective and efficient than traditional pickup and timing tests; plus they will help you truly understand the power system and protective relays. I was first introduced to dynamic testing while learning how to test a motor relay from a small company called Multilin in the 90’s. The 269+Motor Management Relay was THE most popular motor relay at the time, and required some real creativity to test with the manual variac-based test-sets we were forced to use back then. The first big hurdle to overcome was that you had to trick the relay into thinking that the motor was running before you could run a test. That’s step one of a modern dynamic test described above. Then we had to figure out how to test the Mechanical Jam pickup. Unlike other relays, there was no Mechanical Jam Pickup bit, or pickup light, which you could look at that would tell you when the Mechanical Jam protection was operating, so we created steps two and four in the dynamic test procedure. It turns out that this is a much more effective way to test relays and I’m not sure why it took us so long to start applying it to other relays.

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