A key concept in the restructuring of the electric power industry is the ab
ility to accurately and rapidly quantify the capabilities of the transmissi
on system. Transmission transfer capability is limited by a number of diffe
rent mechanisms, including thermal, voltage, and stability constraints. Thi
s paper discusses the available transfer capability (ATC) definitions and d
etermination guidelines approved by the North American Electric Reliability
Council (NERC) and presents several concepts for dealing with the potentia
l errors and technical challenges of computation. (C) 1999 Elsevier Science
B.V. All rights reserved.