Abstract :
When exchange of power is undertaken between adjacent utility companies, a decision must be made as to whether these companies are to be operated as independent units delivering definite, predetermined amounts of power to one another, or whether there is to be unitary operation; that is, operation with a single load dispatcher for the zone and coordinated governing of frequency. This is a matter of far reaching importance, as unitary operation calls for a large measure of operating cooperation and for some degree of common interest.
