*5.3.5. The electric field strength perpendicular to the bisector of the span at the point of the maximum sag*

In the end we examine the consistency of the over ground 400 kV power lines that use covered conductors with the Regulation. We have examined the electric field strength perpendicular to the bisector of the span at the point of the maximum sag, 1 meter above the ground. We use the vector addition in each point, to add the contributions of all phase conductors and their mirror images together. We did this in the same manner as we determined the electrical field intensity at the edge of the insulation of each individual phase conductor. We recorded the highest value of the electric field intensity at each point in the time of one period. We then determined the effective value in accordance with the equation (31). We calculated the points within a distance of 100 meters left and right from the bisector of the overhead power line in steps of 1 m. The results are shown in figure 19.

here:

field intensity is as follows.

*T* is the period,

17.235e+003 V/m.

14.287e+003 V/m.

24.023e+003 V/m.

*maximum sag* 

results are shown in figure 19.

air.

We get the effective value of the electric field intensity by summing over the whole period. By definition, the effective value of the periodic quantity is the one which makes the same effect as the corresponding one-way quantity. In our case the effective value of the electric

2

(31)

0 <sup>1</sup> ()d *T E Et t T*

The highest current value of the electric field intensity in the point (-4.6785; 27.9785) – on the edge of the insulation of the conductor L1 is 24.366e+003 V/m with the effective value of

The highest current value of the electric field intensity in the point (3.9215; 30.9785) – on the edge of the insulation of the conductor L2 is 19.865e+003 V/m with the effective value of

The highest current value of the electric field intensity in the point (5.4785; 25.0215) – on the edge of the insulation of the conductor L3 je 33.813e+003 V/m with the effective value of

From the calculations and figures, we see that the electrical field intensity at the edge of the insulation of any of these three conductors does not exceed the critical dielectric strength of

*5.3.5. The electric field strength perpendicular to the bisector of the span at the point of the* 

In the end we examine the consistency of the over ground 400 kV power lines that use covered conductors with the Regulation. We have examined the electric field strength perpendicular to the bisector of the span at the point of the maximum sag, 1 meter above the ground. We use the vector addition in each point, to add the contributions of all phase conductors and their mirror images together. We did this in the same manner as we determined the electrical field intensity at the edge of the insulation of each individual phase conductor. We recorded the highest value of the electric field intensity at each point in the time of one period. We then determined the effective value in accordance with the equation (31). We calculated the points within a distance of 100 meters left and right from the bisector of the overhead power line in steps of 1 m. The

ef

*E*ef is the effective value of the electric field intensity,

*E* is the vector sum of all the contributing charges.

*5.3.4. The electric field intensity on the edge of the insulation* 

**Figure 19.** The electrical field intensity perpendicular to the bisector of the span in the point of the greatest sag.

The value of the electric field intensity falls under the permitted limit of the regulation at a distance of 30 m away from the bisector of the power line.
