I need your help please There are three turbine-generator units rated 200, 300,

Question

I need your help please

There are three turbine-generator units rated 200, 300, and 500 MVA in an interconnected area of a 60-Hz power system. The regulation constants of the units are 0.05 per unit based on their own ratings. Each unit is initially operating at one-half its own rating when the load suddenly decreases by 100 MW. Determine a) the unit area frequency response characteristic beta in per unit based on 100-MVA base value and in MW/Hz, respectively, b) the steady-state increase in area frequency, and c) the MW decrease in mechanical power output of each turbine. Assume that the reference power setting of each turbine-governor remains constant. Neglect losses and the dependence of load on frequency.

Explanation / Answer

Regulation constants on common system base are (Rpu new = R pu old ( Sbase new/Sbase old): R1 = 0.1; R2 = 0.0667; and R3 = 0.05.

Hence = (1/R1 + 1/R2 + 1/R3) = 45 per unit.

f1 = (-1/) pm = {pm / -(1 + 2)} = ( -100/100) = - 1 Hz.

f2 = (-1/) pm = {pm / -(1 + 2)} = ( -100/200) = - 0.5 Hz.

f3 = (-1/) pm = {pm / -(1 + 2)} = ( -100/400) = - 0.25 Hz.

Assuming pref = 0,

pm1 = (-1/R1)(f) = 0.04444 per unit = 44.44 MW

pm2 = (-1/R2)(f) = 0.06666 per unit = 66.66 MW

pm3 = (-1/R3)(f) = 0.08888 per unit = 88.88 MW

note: see the textbook POWER SYSTEM AND ANALYSIS BY J.DUNCAN GLOVER,THOMAS OVERBYE.YOU WILL GET BEST RESULTS

Related Questions

Navigate

• Browse (All)
• Browse I
• Subjects

---