Line droop

Consider the speed-load (drooping) characteristics of the two machines as shown in Figure 16.20. For ease of illustration, the slopes have been exaggerated. Normally they are within 4% of the rated speed, as discussed earlier. When both machines are loaded equally, the total load may be defined by the load line AA, at the bus frequency,/ When the power input to PMf is increased, so that the drooping curve AO shifts to curve BO, it shifts the load line AA also to BB, so that the total load shared by the two machines will still remain the same. The load shared by G is now more than before at so that , > /, and by Gt less than before at P, so that P < Pi The generators now operate at a higher system frequency, /i,. If the... 

Reactive control can alter the line length ( f LC) to the level at which the system will have the least possible swings. It is evident from these curves that an uncompensated line of a much shorter length may not be able, to transfer even its natural load (Pq) successfully. This is due to the steeply drooping characteristics of the voltage profile at about this load point, which may subject the... 

I am finished picking and head over to check on the red kale and lettuce. They are drooping a bit after being hit with two days of fierce north winds so I set up a line of sprinkler pipe to irrigate them. I open the valve to release water into the sprinkler... 

The scaling factor of a m.p. sequence depends on p (Haeberlen, 1976). A variation of p during the sequence therefore causes a chirp of each resonance. Our simulation program allows us to quantify this effect also. In Fig. 10 we show a simulated BR-24 spectrum of our model system that assumes an exponential power droop that amounts to no more than a 1% decrease of p after 100 BR-24 cycles, that is, after 2400 pulses. Note the asymmetry of the lines and the wiggles at their feet that are indicative of the chirp. In Section IV we present experimental m.p. spectra that display exactly these features. 

Fig. 10. Effect of a droop of the transmitter power on m.p. spectra. An exponential decrease of all flip angles, which amounts to no more than 1% after 100 BR-24 cycles, that is, 2400 pulses, is stipulated. Note the wiggles at the feet of the lines.

A close inspection of the best resolved MREV spectra (b) and (c) in Fig. 22 reveals small wiggles at the feet of the lines. A comparison with Fig. 10 suggests that these wiggles result from a (small) droop of the rf power along the pulse train. Such wiggles are less pronounced in the BR-24 spectra, which comes as no surprise because the duty cycle was only 1 /6 in the BR-24 but 1 /3 in the MREV experiments. 

The droop characteristic line lA-A must be lowered to the new position ID-D so that it crosses the line 2A-D of Gen.2 at point D for 50% sharing of load. Thus the speed... 

If the potential of a heterogeneous mixture is plotted as a function of the mole fraction Xb, a straight line with the slope (/Jg — /5a) and the y-intercept which runs through points (0 and (1 /5g), appears in place of the drooping curve (Fig. 13.5). 

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