# 2016 ASEE Annual Conference & Exposition

## Teaching Protective Relaying Concepts and Testing Methods

#### Presented at Assessment, Course, and Curricular Development

This paper covers problems inherent in teaching electrical power system protective relaying concepts and testing methods at the associate degree level in an electrical engineering technology program. In many cases, these problems are also seen at the baccalaureate level in both electrical engineering and electrical engineering technology. The first, and most difficult obstacle is symmetrical components. The mathematics behind symmetrical components involve complex numbers and linear algebra. While the students are exposed to complex numbers in their AC analysis course and, if required by their program, their electrical machinery course, most of the students have not had a linear algebra course. Another obstacle is power system stability. At best they may have a classical controls and/or dynamics course. This is why in most cases protective relaying is taught at the graduate level or via industrial seminars. Without a background in protective relaying concepts, the testing of the protective relay becomes very prescriptive. The student only learns the specific steps outlined by the relay manufacturer, or in some cases the textbook author, to determine if the relay performed one function correctly.
Most utilities and electrical power system operators need protective relay technicians that understand the electrical power system and how the protective relays function to protect the system in the case of abnormal operating conditions. Simply knowing the output X was set when input Y reached a certain level is not sufficient. The methods used to cover protection of generators, transformers, transmission lines, and busses are discussed. The level of detail in symmetrical components: how they are derived, how they can be recombined to form phase quantities; along with what are the characteristics of the different sequence values, and what sequence quantities are associated with the different fault types are covered. Finally, zones of protection, communication between protective relays, and the subsequent effect on system integrity are also discussed.

Authors
1. Dr. Glenn T. Wrate P.E. Northern Michigan University [biography]