Consider two identical generating units with equal (4 %)speed-droop that operate in parallel
in accordance with the frequency-load characteristics as shownbelow.
(a) If both units are set to operate on curve A and the totalload is equal to 100 % of the rating
of one unit, what percentage of rated kW output is each unitsupplying and what is the
frequency of the common busbar?
(b) Repeat (a) if the total load is equal to 200 % of the ratingof one unit.
(c) If one unit is set to operate on curve B (while the otherremains operating on curve A) and
the total load is equal to 100 % of the rating of one unit, whatpercentage of rated kW
output is each unit supplying and what is the frequency of thecommon busbar?
(d) Repeat (c) if the total load is equal to 150 % of the ratingof one unit? How would you
characterize operation with any further increase in totalload?.
         Frequency                      Generator Rated Load %
AÂ Â Â Â Â Â Â Â 106-102Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â 100
BÂ Â Â Â Â Â Â Â Â 104-100Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â 100
