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Surge voltage of 1000 kV is applied to an overhead line with its receiving end open. If the surge impedance of line is 500 ╬й, then total surge power in the line is
2000 MW
500 MW
2 MW
0.5 MW
2000 MW
The surge power is defined by the relationship between the applied voltage and the surge impedance of the transmission line. Since the surge is a traveling wave, the power it carries is calculated as the square of the voltage divided by the surge impedance, representing the instantaneous power associated with the propagating wave.
The surge power is defined by the relationship between the applied voltage and the surge impedance of the transmission line. Since the surge is a traveling wave, the power it carries is calculated as the square of the voltage divided by the surge impedance, representing the instantaneous power associated with the propagating wave.
P=Z0тАЛV2тАЛ тАФ formula for instantaneous surge power
I=Z0тАЛVтАЛ тАФ formula for surge current
When a surge voltage V enters a transmission line, it establishes an electromagnetic wave. The surge impedance Z0тАЛ determines the ratio of voltage to current (V/I) for this wave. The power P delivered by this surge is given by P=V2/Z0тАЛ. For a 1000 kV surge on a 500 ╬й line, the calculation is (1000├Ч103)2/500=1012/500=2├Ч109 Watts, which is 2000 MW.
Surge impedance Z0тАЛ=CLтАЛтАЛ is independent of the length of the line.
The power carried by a traveling wave is purely resistive in nature as Z0тАЛ is real for lossless lines.
The open receiving end causes total reflection, doubling the voltage but resulting in zero current at the terminal.
Provides a simple metric to assess the impact of lightning or switching transients.
Helps in selecting insulation levels (BIL) for high voltage equipment.
Does not account for frequency-dependent losses in practical lines.
Assumes a rectangular wave front which is an idealization.
Insulation coordination in EHV and UHV substations.
Design of surge arresters and protective devices.
Calculation: P=500(106)2тАЛ=5001012тАЛ=2├Ч109W=2000MW.
Option B, C, and D are incorrect as they do not satisfy the mathematical relation P=V2/Z0тАЛ.
A is correct тАФ The surge power is calculated using P=Z0тАЛV2тАЛ, yielding 2000MW.
Always convert voltages to Volts and impedances to Ohms before calculating power to avoid magnitude errors in the final result.