The Ferranti effect is a phenomenon observed in long transmission lines, particularly under light loading or no load conditions. The characteristics of the Ferranti effect include:

(i) Flow of unduly heavy current: This characteristic is generally not directly associated with the Ferranti effect. The effect is more relevant to voltage rise rather than heavy current flow, which can occur under different circumstances.

(ii) It occurs at unloaded condition: This is a true characteristic of the Ferranti effect. It is most pronounced when the transmission line is lightly loaded or completely unloaded.

(iii) Rise in the receiving end voltage: This is a defining feature of the Ferranti effect. Under no-load or light-load conditions, the receiving end voltage can rise above the sending end voltage due to the capacitive nature of long transmission lines.

In summary, the Ferranti effect is characterized by its occurrence under unloaded conditions and the rise in receiving end voltage, but it doesn’t typically relate to unduly heavy current flow.

To calculate the capacitance to neutral per kilometer of a three-phase transmission line, we can use the formula for the capacitance per unit length for a three-phase line with flat horizontal spacing.

The capacitance to neutral (C) can be calculated using the following formula:

[

C = frac{2 pi varepsilon_0}{ln(frac{D}{r})}

]

Where:

– ( varepsilon_0 ) is the permittivity of free space, approximately ( 8.854 times 10^{-12} , text{F/m} ).

– ( D ) is the distance between the conductors.

– ( r ) is the radius of the conductor.

1. The distance ( D ) between the conductors is given as 3.5 m.
2. The radius ( r ) of each conductor can be calculated from the outside diameter:

– Outside diameter = 1.05 cm = 0.0105 m, so the radius ( r = frac{0.0105}{2} = 0.00525 , text{m} ).

Now substituting these values into the formula:

1. Calculate ( ln(frac{D}{r}) ):

[

D = 3.5 , text{m} quad text{and} quad r = 0.00525 , text