[James_H._Harlow]_Electric_Power_Transformer_Engin(BookSee.org)

FIGURE 2.9.40A Circuit diagram corresponding to a resistor in parallel with a fully modeled reactor, i.e., one having
series resistance.
FIGURE 2.9.40B Q-vs.-frequency characteristic of a reactor with parallel resistor.
FIGURE 2.9.39 Tapped filter reactor with de-Q’ing rings.
2 2 2
2
( LL
1 2
M L2)
R2
L
Q
2 2 2 2
( RM RLRR)
2
(2.9.45)
where
L 1 = self inductance of reactor, H
L 2 = self inductance of de-Q’ing ring system, H
M = mutual inductance between reactor and de-Q’ing ring system, H
R 1 = series resistance of reactor,
R 2 = resistance of de-Q’ing ring system,
The shape of the Q-vs.-frequency characteristic depends on the value of the coupling factor and also
on the values of the series resistance and load resistance. Figure 2.9.41b is a typical characteristic for a
practical reactor plus d-Q’ing ring system. It is seen that the Q curve has both a maximum and a
minimum. In general, the maximum depends mostly on the series resistance, while the minimum depends
primarily on the coupling factor and the ring resistance.
2.9.7.3 Summary
Figure 2.9.42 contains a graph of Q vs. frequency for a natural Q-filter reactor, a filter reactor plus parallel
resistor, and a filter reactor with a de-Q’ing ring system. Note the virtually identical Q-vs.-f characteristic
for the parallel resistor-vs.-de-Q’ing-ring option.
1 2
1 2
2
FIGURE 2.9.41A Circuit diagram for a reactor with a de-Q’ing ring.
FIGURE 2.9.41B Typical graph of Q vs. frequency for a reactor plus de-Q’ing rings.
© 2004 by CRC Press LLC
© 2004 by CRC Press LLC