Theoretical Approach to Speed and Tie Line Control

Frequency error is an indicator of the amount of excess or deficiency of generation on a whole interconnection, and a frequency-generation line may be established for the whole or for any section which is separated from all others by tie lines over which control may be desired. Automatic equipment is available using these fundamentals under the name of load biased frequency control, which will make the required adjustments to generation to restore normal speed and tie line loadings with a minimum of false moves and by means of which each section will handle, in normal operation, only its own load changes, regardless of the speed of response of its prime movers to correcting impulses. Methods of automatic control by the selective frequency blocking system and the master flat frequency station method are examined and found wanting. The use of uncontrolled speed-sensitive governors with small droop is shown to be disadvantageous if operated in parallel with automatic bias equipment. Consideration is given to practical matters of operation, including an improvement in handling manual generation shifts, action of controller in time of trouble, effect of errors in determining the frequency-generation line, and desirable characteristics of governors.