Send and receive short end of the line can be seen in the same amount of
current flow. So here it is, is that the parameters R and L s no one here,
stacked line (lumped) state.
Short length of the line performance test (performance test) in the
voltage regulation and efficiency of transport was the most important.
Classification of overhead transmission line:
Transmission line three constant R, L and C lines along the entire
length of the trance line wide. R,L,C
Series impedance the other two lines in
the shunt path (shunt path) formed. Calculation of the Transmission line
effects capacitance so that is another complication. Based on the Transmission
line is divided into three sections, namely: -
1. Short length of the Transmission Line
2. Medium or medium Transmission Line
3. Long or Long Transmission Line.
Short Transmission Line:
When the line length of 50 km And line voltage between 20 Kv Below is a
short line of the Transmission Line is considered. Short length of the line
voltage is low because it was not responding capacitance. Short Transmission
Line and inductance calculation resistance only are taken into account. This line of
constant (constant) s along the entire length of the uniform is not detailed
here, but no one stacked (lumped) are considered.
Medium Transmission Line:
When the line length of 50 - 150 km. And the voltage of 20-100 kv bottom
line is, when the line is considered as a Medium Transmission Line. The length
of the line voltage is high because capacitance response. Along the entire
length of the line expanded balance capacitance. capacitance line predominates,
but for the benefit of one or more of the Calculation shunt condenser middle points as is.
Long Transmission Line:
When the line length of 150 km. The above and the line voltage > 100
kv, and then the line is considered as a Long Transmission Line. The names of
one or more lines of constant throughout the line, but the point is not middle
points as stance line split is considered and rigorous method is applied to
solution .
Equation to calculation the voltage regulation of short overhead
transmission line:
Transmission line is when the current flow, the drop in the transmission
line cable reactance , resistance and end voltage Vr is less than the voltage
Vs for the receiving end. Receiving end voltage Vr of the percentage of the amount of voltage
drop (ie,
Vs-Vr) is the voltage of the Regulation. Thus,
Voltage regulation is defined as the percentage rise in receiving end voltage
when full load is thrown off, the sending end voltage remaining the same.
% V R = Vs - Vr / Vr × 100
Solved Problem on Voltage regulation and efficiency of overhead short
transmission line:-
1. Industry ones 3-Ø, 11 Kv 0.8 lagging power factor load line to
receive the 1.2 MW. 2.5 Ω to 3.5 Ω reactance
or resistance cable conductor and Voltage Regulation of Transmission of
determining the percentage of tax.
Ans:-
3 - Ø line Vr (line) = 11kv
Vr / ph = 11000 / √ 3 = 6350.85v
Pr = 1.2 MW = 1.2 × 1000000W
Cosθr = 0.8
lagging
Θr = cos-¹ 0.8 =
36.86
R / ph = 2.5 Ω or XL / ph = 3.5Ω
Z / ph = 2.5 + j 3.5 = 4.3 <54.46
% Age Voltage regulation =?
Transmission affiance η =?
We know that,
Vr / ph reference vector
= 6350.85 <0 ̊ V
Ir = Pr / √ 3 Vr cos Ø
= 1.2 × 1000000 / √ 3 × 1000 × 0.8
= 78.73 A
Ir = 78.73 <-36.86 ̊ A w.
r. t. Vr
voltage drops(ph)
Ir Z / ph = 78.73 ˂ -36.86 ̊ × 4.3 ˂ 54.46 ̊
=
338.53 ˂ 17.6 ̊ = 322.7 + j 102.36 V
Now,
Vs / ph = Vr / ph + Ir Z / ph
=
6350.85 + 322.7 + j 102.36
=
6673.55 + j 102.36
=
6674.33 ˂ 0.87 ̊ V
Or
Vs line =
√ 3 × 6674.33 = 11560.28 V = 11.56 kV
% Age Voltage regulation = Vs - Vr / Vr × 100
=
11.56 - 11/11 × 100
=
5.09%
Line loss = 3I ² R
=
3 × (78.73) ² × 2.5
=
46488 W
=
Transmission line of sending power = receiving power + line loss
Ps = Pr + 3I ² R
=
1.2 × 1000000 × 46488 = 1.25 × 1000000 W
Transmission affiance η = Pr / Ps × 100
=
1.2 × 1000000 / 1.25 × 1000000 × 100
=
96.27% (Ans.)
Others Question & Answer: -
1. What a load of regulations is positive?
Answer: - unity lagging power factor and load regulation
are positive.
2. When negative voltage is Regulation?
Answer: - When the line is connected to capacitive
load, the load p.f. Leading Edge is waiting to receive and transmit high
voltage side can be found. The voltage regulation is negative.
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