Activities, Opportunities, and Items of Interest for Members
November  2019 Edition
Welcome to the November Edition.  Future editions bringing the latest news and updates will be published each month.
You might find it helpful to bookmark this site for future reference:
Perry Sprawls, Editor.         Robert Pettigrew, WNC IEEE Co-Editor.
The WNC IEEE Website:
Enriching Student Educational With Shared Experiences

Within the membership of the Western North Carolina Section of the IEEE there are many years of collective professional experience in the application  of engineering knowledge in "real world"  projects and programs. This not only includes engineering knowledge but also valuable perspectives of the engineering process that comes with on-the-job activities.  This is a valuable resource that can make significant contributions to the education of students and younger members of the profession through a various activities based on a variety of models generally relating to subject matter, methods of sharing, and the students or others who will benefit. The opportunities are with the local institutions, student organizations, WNC IEEE continuing education programs, and beyond. 

In this and future editions of this Newsletter the focus will be on specific models and opportunities for sharing experience, provide examples, and encourage members to become involved.  For information on programs and opportunities for involvement contact:

WNC IEEE Secretary, Audie Burke .


WNC IEEE  Continuing Education and For WCU Students

Presented by
Robert D Pettigrew,

  • Date: 13 Nov 2019
  • Time: 05:30 PM to 07:30 PM
  • WCU Engineering
  • 389 Centennial Drive
  • Cullowhee, NC , North Carolina
  • Building: Belk Building
  • Room Number: 324
  • Co-sponsored by WNC Power Engineering Society

With the decision to construct the US power system with three phase power there came the problem of how to analyze unbalanced system faults. With single phase power analysis was very simple however with three phase power the analysis was quite complex.

 In 1918 C.L. Fortesque presented a paper, at an AIEE meeting, describing how a set of “n” unbalanced phasors could be represented by “n” sets of balanced phasors. The paper was judged to be the most important power engineering paper in the twentieth century.



 In 1926 Edith Clark presented a technical paper to IEEE regarding Symmetrical Components that described how unbalanced three phase power could be analyzed by using three sets of balanced phasors. (Positive, Negative and Zero sequence) Edith Clarke also wrote an influential textbook in the field of power engineering, Circuit Analysis of A-C Power System.





This discussion mainly reviews how to calculate these phasors and introduces how to use these phasors to analyze unsymmetrical faults in the power system. Simple examples are reviewed. The power grid consists of many sources and a vast array of interconnected lines that supply power to the customers. The majority of faults on the system are unbalanced and require a method to calculate fault currents and voltages in order to properly set the protective relays on the system. Symmetrical component analysis enabled the engineer to more efficiently produce these values.

In today’s environment sophisticated system computer models are used to calculate fault values. However, an understanding of symmetrical components will assist the engineer to interpret the data produced by these programs.

From Western North Carolina to the World
Perry Sprawls, WNC IEEE member living in Black Mountain uses the internet to share his experience as an engineer and medical physicist with institutions and students all over the world. 

This is through the Sprawls Educational Foundation on the web at: . .
The map below shows locations of institutions and students that are actively online with the Resources based in Western North Carolina.