Problems, Not Just on Transmission Lines
Charles Bayless recently retired as President and Provost of the West Virginia University Institute of Technology. Previously he was Chairman, President, and Chief Executive Officer of Illinova Corporation and its wholly owned subsidiary, Illinois Power Company. Prior to joining Illinova Corporation, he was Chairman, President, and Chief Executive Officer of Tucson Electric Power Company.
"Be Obscure Clearly" - E. B. White, The Elements of Style
In 2003 the National Academy of Engineering released its list of the greatest engineering achievements of the 20th century. In first place was the electric grid.
No part of the grid seems to be more obscure or misunderstood than reactive power. "It's like the head on a glass of beer," is one of the amusing descriptions of VARs. But to understand the operation, limitations and problems facing our transmission system as we transition to the greater use of renewables, an understanding of VARs is critical.
"VAR" stands for Volt-Ampere-Reactive. VARs come in two basic types, capacitive and inductive. Transmission and distribution lines both generate both types of VARs, while loads usually generate inductive VARs.
See Figure 1.