Available Power

in an electric power system, the portion of the total system power that can be used by a dispatcher to meet the system’s loads (power demand). The amount of available power is defined as the total power of the system’s generators minus the power of the generators undergoing repair. Ordinarily, the available power is greater than the demand; the difference between the two values constitutes the reserve that is used to meet sudden load peaks.

In the normal operation of an electric power system, the available power must not be less than the demand at any given moment. If this condition is violated, a power deficit develops in the system that can lead to a lower quality of electric power in the form of a change in the frequency and voltage. In the most severe cases, damage may occur. A deficit can be met by using power supplied over power transmission lines from other systems. If the available power is to be utilized completely, the power transmission lines and the elements of the electrical network should have adequate transmission capability.