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

We discussed how waveforms and frequencies are created in the high voltage electrical world in our first online protective relay training course, The Three-Phase Electric Power System.  Waveform drawings depict every detail of a power system, but you have to be a special kind of person to look at a waveform drawing and accurately understand what is happening in any given moment. Phasor drawings were created to simplify waveform drawings into a diagram that can tell you a lot about the electrical system at a glance.

This phasor diagram online training course will show you how to convert waveform drawings into phasor diagrams so that you understand what is happening under the hood of protective relays, electrical meters, and protective relay test-sets to help you become a master at drawing and understanding phasor diagrams.

Phasor diagrams represent a common language that helps communicate complex information between electrical personnel and equipment, so you would think it would be important that all devices and personnel speak the same language. Unfortunately, phasor diagrams can be drawn using several different “dialects” depending on the manufacturer and model of the equipment, and the background of the personnel. A phasor drawn at 120° on a phasor diagram from Megger would be represented as -120° on Omicron test-sets or 240° on Doble test-sets. Some relay manufacturers can’t even agree on the correct angle designations within their own product lines.

This course will demonstrate all of the different phasor diagram “dialects” so that you will be able to recognize any phasor diagram dialect, correctly interpret it, and then be able to convert it into another dialect so that you can test any relay with any test-set.

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

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.

What You Need to Take the Course

Most of the course content uses the Vimeo streaming video service, which is the equivalent of YouTube (without the ads, of course). You need a good internet connection, a computing device that can stream video, and some privacy (or headphones) to watch the videos. You can make all videos full screen by clicking the “Enter Full Screen Icon” on the bottom right hand side of the controls.

Most of the exercises use Adobe PDF format along with online quizzes, so you will need a PDF viewer to view the exercise sheets and a printer to print them out.

A few exercises require measurements.  You can use a ruler and calculator for these, or you can use scissors to cut out the rulers on the exercise sheets.

A few practice exercises have been created in Microsoft Excel, so you will need some version of Excel.  If you do not have access to excel, contact [email protected] with your free spreadsheet software of choice, and we will try and create a version for you.

You can ask questions about any topic in the comment section, or ask unrelated questions in the course forums.  We read and respond to every comment we see!