# Power Systems Questions and Answers – Electric Field and Potential of a Long Straight Conductor – 2

This set of Power Systems Interview Questions and Answers for Experienced people focuses on “Electric Field and Potential of a Long Straight Conductor – 2”.

1. If we account for the effect of the presence of the capacitance of the transmission line, then the capacitance ___________
a) increases
b) decreases
c) remains same
d) increases hyperbolically

Explanation: Earth effects increases the capacitance of the system.

2. While estimating the line parameters, the term self GMD is used for the calculation of ______________
a) inductance
b) capacitance
c) conductance
d) inductance, capacitance and conductance

Explanation: Self GMD is used in the calculation of the inductance.

3. The ground effect causes line capacitance to _____________
a) Increase by 0.2%
b) Increase by 2%
c) Decrease by 0.2%
d) Decrease by 2%

Explanation: The effect of the ground is not very significant on the capacitance.

4. If the spacing between the phase conductors is increased, the line capacitance will _______________
a) decrease
b) increase
c) remain same
d) depends on the conductor

5. If the length of the transmission line is increased, the line charging current in the TL will _____________
a) increase
b) decrease
c) remain same
d) not be affected

Explanation: If the length of the TL increases, then the line admittance will decrease, so the line charging current will decrease.

6. On applying the alternating sine wave as the input to the line, the line capacitance draws _____________
b) lagging sinusoidal current
c) current in phase with voltage
d) depends on the receiving end load

Explanation: The line current will be leading sinusoidal current.

7. The capacitance becomes significant for the __________
a) long transmission line
b) medium transmission line
c) short transmission line
d) cannot be determined

Explanation: Capacitance parameter is highly important for long transmission line due to the charging current flowing in the LTL.

8. The method of the images is applied to find the __________________
a) calculation of capacitance
b) calculation of inductance
c) calculation of resistance
d) calculation of effect of the earth on capacitance

Explanation: Method of images given by Lord Kelvin is used to calculate the effect of the earth on capacitance.

Sanfoundry Global Education & Learning Series – Power Systems. 