A generating station comprises four 125 kVA, 22 kV, 0.84 pf lagging synchronous generators With a frequency drop of 5 Hz from no-load to full-load, at a frequency of 50 Hz, three generators supply a steady load of 75 MW each while the balance is shared by the fourth generator (called swing generator).
(a) For a total load of 260 MW at 50 Hz, find the no-load frequency setting of the generators.
(b) With no change in governor setting as in part (a), find the system frequency if the system load rises to 310 MW.
(c) Find the no-load frequency of the swing generator for the system frequency to be restored to 50 Hz for the load in part (b).
(d) Find the system frequency if the swing generator trips off with the load as in part (b), the governor setting remaining unchanged as in part (a).