ABSTRACT
Transmission systems must meet performance standards and criteria that ensure an acceptable level of
quality of electric service. Service quality means continuity of supply and constancy of voltage waveform
and power system frequency. Frequency is typically not an issue in large interconnected systems with
adequate generation reserves. Similarly, voltage quality at the consumer connection is typically addressed
at the distribution level and not by reinforcing the transmission system. This leaves continuity of power
supply as the main criterion for acceptable transmission system performance.
