Consider a load impedance of Z = j w L connected to a voltage and V let the current drawn be I . (a) Develop an expression for the reactive power Q in terms of ω , L , and I , from complex power considerations. (b) Let the instantaneous current be i ( t ) = 2 I cos ( ω t + θ ) . Obtain an expression for the instantaneous power p ( t ) into L , and then express it in terms of Q. (c) Comment on the average real power P supplied to the inductor and the instantaneous power supplied.
Solution Summary: The author explains the expression for reactive power and instantaneous power in terms of L and Q.
Consider a load impedance of
Z
=
j
w
L
connected to a voltage and V let the current drawn be I.
(a) Develop an expression for the reactive power Q in terms of
ω
,
L
, and I, from complex power considerations.
(b) Let the instantaneous current be
i
(
t
)
=
2
I
cos
(
ω
t
+
θ
)
. Obtain an expression for the instantaneous power
p
(
t
)
into L, and then express it in terms of Q.
(c) Comment on the average real power P supplied to the inductor and the instantaneous power supplied.
A transmission line delivers 1200MW at 500kV and 85% power factor. The series impedance of the line is 0.42 + j0.65 ohms/mi and the shunt impedance to.neutral is -j0.12 x 10^6 ohms-mi. What is the velocity propagation of the line.
A. 560 × 10^6 km/hr
B. 890 × 10^6 km/hr
C. 750 × 10^6 km/hr
D. 510 × 10^6 km/hr
Q5. A single phase overhead transmission line has a supply voltage of 34 kV and a sending end current of magnitude 40 A at 0-8 p.f. lagging is feeding a certain load. The total resistance and inductance of the line are 5 and 21 mH respectively. Draw the practical circuit used and the devices necessary to perform this experiment. Then calculate the sending end power, receiving end current, voltage, power factor, receiving end power and line efficiency Vs 34000 Is 40 Cosos 0.8 R 5 Ps Ir Vr Cosor Pr n 21e-3
A transmission line of impedance (0.05 + j0.02) pu interconnects the buses
of a switchyard and a bulk supply point. The receiving end apparent power
is (1.0 + j0.6) pu and sending end voltage, 1/0°pu. Estimate the following:
i) Receiving end voltage after two iterations
ii) Perform two further iterations to test the convergence of the value of
receiving end voltage deduced in (i)
iii) load current
Chapter 2 Solutions
Power System Analysis and Design (MindTap Course List)
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