Online Course 1-1: The Three-Phase Power System (4 NETA CTDs)

4.92 out of 5 based on 12 customer ratings
(13 customer reviews)

$24.95 USD

Online Training Course, 4 CTDs

Protective relays are on a hair trigger as they constantly look at the three-phase electric power system and try to decide whether the system is normal, or under fault conditions. If they detect a fault, they will attempt to isolate that fault from the rest of the electrical system.

Electro-mechanical relays use magnets and mechanisms to look for specific problems on the three-phase power system, and each relay model should have identical functions and wiring. This allows relay testers to follow a script that creates the specific criteria required to make the mechanisms move, and prove that that specific function is operating correctly. Relay testers do not need to understand the three-phase power system when testing this generation of relays because the relays are identical and perform simple functions.

Modern digital relays can be extremely complex with interactions between elements and endless logic configurations. This means that two identical relay models can have completely different functions. While it is possible to carry the electro-mechanical testing philosophy into the digital realm by re-programming the relay when testing each element, this style of testing will not prove that the relay will operate when required. A relay tester who understands the three-phase electrical system can build test plans that test the entire relay, instead of individual pieces of it, to make sure the relay operates when required. These procedures can also be more effective and efficient than traditional test procedures.

We will cover the following topics in this lesson to give you a foundation in three-phase electrical theory to help you become a better relay tester:

Introduction to Electrical Fundamentals and Frequency

  • How electricity is created
  • What is a cycle
  • How to count cycles
  • Understand how frequency and cycles are related
  • Converting cycles to seconds
  • Converting seconds to cycles
  • Converting cycles to cycles

Three-Phase Electric Power Systems

  • How three-phase electric power systems are created
  • How to determine what kind of three-phase electric power system is being generated
  • How to change one kind of three-phase electric power into another

You might see this list and think that you already have a firm grasp on these topics. Test your knowledge with this quick quiz:

Test Your Knowledge

 If you can’t answer all of the questions correctly,

Sign Up for the Course Today

 Not sure if online training is right for you?  Watch these two videos to see what skills you need for online training and how to navigate the online training course here at Valence Electrical Training Services.

Introduction to Online Training

online protective relay training introduction

All of our online training videos use Flash technology that should work on all Windows computers or tablets. You can view the course on Android tablets with the Dolphin Browser for Android, or on an iPad with the free Puffin Web Browser.  We found that the paid version of Photon Flash Player for iPad had better performance on an iPad.


The The Three-Phase Power System online training course is eligible for 4 NETA Continuing Technical Development Credits (CTDs). NETA Certified Technicians (Level III and Level IV) are required to earn a minimum of 48 CTDs every three years to maintain their certification. For more information about the CTD program and requirements, please contact the NETA office at or 888-300-6382.

Do you want to enroll more than one person to our online training courses?  No problem!  Click the “Enable Group registration” checkbox at the bottom of any course, then choose how many people you want to register before you click “Add to Cart”.  All bulk and coupon prices will still apply. You control who gets enrolled to the course via the “Group Registration” page. Enroll one at a time, or upload your entire team via a simple csv file. We’ll automatically create everything they need to start the course and send them an email with their user name, password, and course links.

13 reviews for Online Course 1-1: The Three-Phase Power System (4 NETA CTDs)

  1. 5 out of 5

    (verified owner):

    I found this course to be very useful in understanding the fundamentals of three phase power systems. It was extremely easy to follow along. Very clear, cadenced rhythm with the video narration allowed me to understand without having to backtrack.

    The course material would be suitable for technicians or students looking to get a grasp on three-phase power systems and converting between cycles and seconds; a must have for any relay technician.

    I appreciated the real world examples and exercises, which will help me when I come across these specifics problems in the microprocessor based world of protection relays.

    Overall I highly recommend this course!

  2. (verified owner):

    I learned a lot from this course. Having no relay testing experience, I was grateful the real world examples were shown. I will definitely continue with this program, as they become available

  3. 5 out of 5


    very informative

  4. 5 out of 5


    Great fundamental courses, preparing you for any relay testing out there.

  5. 5 out of 5


    Excellent refreshers for someone in the field who doesn’t deal with phasers and/or frequency/time/cycles conversions very often.

  6. 5 out of 5


    Great for satisfying NETA training requirements.

  7. 5 out of 5


    Why should someone take this course?

    “To prepare you for a career in relaying protection.”

  8. 5 out of 5


    If you want to improve your overall knowledge of three phase power systems you should take this course

  9. 4 out of 5


    Very good course to take online!

  10. 5 out of 5


    Relay Testing Class Evaluation

  11. 5 out of 5


    If you are in relay P&C, you need this course for success in your field

  12. 5 out of 5


    The course was easy to follow along, very interactive, and descriptive.

  13. 5 out of 5


    In order to clarify already understood concepts and learn new ones in order to make themselves a more confident and reliable relay tester and commissioning tech. Also to be able to mentor in the correct manner to hopefully eliminate some of the so many bad habits of testers in the industry.

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$24.95 USD

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