Online Course 1-2: Phasor Drawings for Relay Testers (4 NETA CTDs)

Phasor diagrams are your one-stop-shop for understanding an electrical system at a glance. You’d think that all of the relay test-sets, phase-angle meters, and relays would use the same angle systems to communicate this important information to prevent confusion. Unfortunately, you’d be wrong.

Imagine you’re testing an SEL relay using a Doble test-set and RTS software and you set up a simple three-phase, balanced, metering test (ABC). Each device would display the following angles during a typical meter test:

  1. A-Phase voltage = 0 degrees, B-Phase voltage = 120 degrees, C-Phase voltage = 240 degrees
  2. A-Phase voltage = 0 degrees, B-Phase voltage = -120 degrees, C-Phase voltage = 120 degrees
  3. A-Phase voltage = 0 degrees, B-Phase voltage = 240 degrees, C-Phase voltage = 120 degrees

Can you confidently match the angle system to the device? (Write down your answers and click to compare {RTS = ?, SEL = ?, Doble = ?})

RTS = 1, SEL = 2, Doble = 3


If you don’t know the difference between devices, you won’t be able to:

  • Perform a meter test properly (more on meter tests in the future)
  • Create effective test-plans
  • Troubleshoot test-plan problems

Can you believe that there is a fourth angle system out there we haven’t mentioned yet?

Sign Up for the Course Today ($49.95 USD)

This course will introduce you to phasors and show you how to convert waveform drawings into phasor drawings so that you can understand what phasors are and how they are created.  You will be able to understand what is happening inside your relay and test-set with these topics:

  • What are Phasors?
  • How to Draw Phasor Diagrams
  • Drawing Phasors with Lagging Angles
  • Drawing Phasors with Different Scales

In a perfect world, these four lessons would be all you needed to become a phasor drawing master. You would be a master at understanding and drawing phasor diagrams in Megger test-sets and GE SR relays but, unfortunately, it seems every manufacturer has a different system for the angles in phasor drawings.  The remaining lessons in this course will help you understand all of the different angle systems used by test-sets from Doble, Omicron, and Manta Test Systems as well as the angle systems used by GE UR and SEL relays:

  • Draw Phasors with Positive Angles
  • Draw Phasors with Negative Angles
  • Draw Phasors with Positive and Negative Angles

You get immediate access to the course if you pay with a credit card. All of our online courses include:

  • High-quality video presentations introducing you to theory behind the topic to help you understand how it works
  • Real-world examples that show you how to apply the theory
  • Interactive exercises and quizzes that simulate the most realistic situations possible to help you learn by doing
  • A comment section where you can ask your questions and get your answers from instructors or fellow students

Sign Up for the Course Today ($49.95 USD)

You can watch a 10-minute video below that will give you an introduction to the topics covered in this course.

Still not sure if this course is right for you? 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 ($49.95 USD)


This 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 [email protected] or 888-300-6382.

Do you want to enroll more than one person into our online training courses?  No problem!  

Go to our Team Registration Page at the Valence Training Academy

Click Here To Buy Courses For Multiple Students or Another Person

You control who gets enrolled into the course via the “Manage Teams” 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.

Click the “Add to cart” Button Below To Purchase This Course For Yourself! 

43 reviews for Online Course 1-2: Phasor Drawings for Relay Testers (4 NETA CTDs)

  1. Anonymous Student

    practicing always make you better having course material teaching you and showing you gives you a better understanding of what a phasor is

  2. Anonymous Student

    This course allows anyone with little or no knowledge to have an overview of how electrical devices works.

  3. Peter Cogswell, NETA III, NICET III

    The information in this course was very well presented. The practice sheets make the concepts more easily understood. I would recommend this course to anyone who is involved with Electrical Power Systems.

  4. Ahmad Shabazz

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

  5. Post-Course Evaluation Form Comments

    Very good explanations on phasors and testing.

  6. Customer Review Form

    Excellent for NETA CEU’s

  7. Student Review

    Great tool!

  8. Course Review

    This course is a must for anyone that is responsible for testing or maintaining Power Systems.

  9. Course Review

    You should take this course “to further their understanding of 3 phase phasors and vectors”

  10. Course Review

    It is something that is required for the Modern Test Engineer

  11. Customer Review

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

  12. Customer Review

    Anyone who loves to be a relay engineer, Chris is the guy who can teach you so well, who can make you be what you wanted to be as a relay engineer.

    He is Second to none when it comes to teaching about relays. He is the Guru :)

  13. Rob P.

    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.

  14. customer review

    For people who feel they may know some details about relay testing but get confused by the different phase angles and phase rotation. It clears up the differences and opens your eyes to the need to be careful when trying to figure out phase rotation.

  15. A Relay Course Evaluation

    There isn’t a better, more thorough introduction to phasors that I’ve seen online.

  16. A Relay Course Evaluation

    This is one of the most helpful course for who is working on the field of switchgear and who willing to work on switchgear sector

  17. customer review

    How did the course help you?
    Totally understanding how to deal with the phasor diagrams which I do need to test and commission protection relays
    How do you feel about relay testing now?
    Much easier to test
    Why should someone take this course?
    It will help you to improve the testing skills much more than only practicing with no scientific knowledge

  18. A Relay Course Evaluation

    If you want to take your relay testing knowledge to the next level, this course is a must!

  19. A Relay Course Evaluation


  20. A Relay Course Evaluation

    If you don’t have any experience about relay testing, this will be little bit hard to understand. However, in my case, I just watched this course so many times before relay testing and now, I can go on right way to do it with confidence. This is really valuable for your carrier as relay tester.

  21. A Relay Course Evaluation

    How did you feel about testing relays before the course?
    I have never experienced before and just did bench top relay testing.
    How did the course help you?
    increase my knowledge regarding protection relay world and now I did my first job of SEL-700G for FAT testing.
    How do you feel about relay testing now?
    Very exciting and there are lots of fun and interests.
    Why should someone take this course?
    to verify their knowledge with other expert. since sometimes, they are very stubborn and tend to believe their experience.

  22. A Relay Course Evaluation

    I’ve done enough coursework in my life in various disciplines and trade crafts to have forgotten some of them. In all of my studies, I have rarely met an instructor who knew their material better, delivered it more clearly and effectively, or who obviously enjoyed teaching their subject more. His class helped me understand relay testing at a level far above what I knew before I took it. It would be difficult to overstate the value of his classes.

  23. Public Review

    How did the material help you?

    Course was easy to follow and navigate

  24. Public Review

    Very good training to help someone understand what to look for in phase relationship with what you will see in the real world of relays.

  25. Protective Relay Training Class/Course Evaluation Form

    do the practice it will help in the end

  26. Protective Relay Training Class/Course Evaluation Form Response

    What would you tell someone who was thinking about taking the course?

    Take it and do the hands on exercises

  27. Public Review

    The material is really hand on and helpful.

  28. Protective Relay Training Class/Course Evaluation Form Response

    It is good training to understand plotting Phasors.

  29. Protective Relay Training Class/Course Evaluation Form Response


  30. Protective Relay Training Class/Course Evaluation Form

    They should definitely take the course.

  31. Ken Z

    Great explanation of AC & DC circuits.

    Different manufactures have a different reference, but knowing this helps explain some of the readings that I’ve had trouble with in the past.

  32. Protective Relay Training Class/Course Evaluation Form

    It is a definite must have for a relay tester!

  33. Protective Relay Training Class/Course Evaluation Form

    Great for beginners and journeymen

  34. Test live_Page_0dollar

    this course is good whether you don’t know phasors or need a refresher

  35. Protective Relay Training Class/Course Evaluation Form

    Absolutely worth it.

  36. Protective Relay Training Class/Course Evaluation Form

    go for it if you want to understand phase rotation and how to draw phasor diagrams

  37. Tyler H. with Electrical Reliability Services Inc,

    Great idea and I actually learned quite a bit. I think this is a great avenue for training.

    I think this will help me a lot in future applications. I saved the provided excel sheet for future use.

  38. Forest Vallad

    Every NETA technician level 2 and up need to have this under their belt.

  39. Course Review

    I would definitely get this online training. Its broken down to the basics and takes you through a step by step process. You cant go wrong with this. It is worth every penny. It even has websites you can research if you’re unfamiliar with the material.

    The videos and presentations on this course have been very helpful and given me a better edge on what is going on in the relay testing industry.

  40. Protective Relay Training Class/Course Evaluation Form

    take it

  41. Protective Relay Training Class/Course Evaluation Form

    This course will help you sort out which brands use which system to depict phase angles. That is super handy in the field.

  42. Protective Relay Training Class/Course Evaluation Form

    It is a good refresher on how to draw or troubleshoot using phasors.

  43. Protective Relay Training Class/Course Evaluation Form

    I encourage anybody interested in power system engineering to take this course. Thank you for having this course offered online, this is a big help like me especially that I am away “literally” for the training center (considering that I am from Southeast Asia). Thanks again.

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$49.95 USD

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