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Operation and Maintenance
2.6.6
Measuring the Ground Resistance
See Fig. 2-31
Three measurements must be performed over a large area in order to determine the ground resis
tance precisely. The distance between 2 auxiliary grounds required must be large in relation to the
complete ground network of the navigation installation. Two steel rods approx. 1 m long should be
used as auxiliary grounds (reinforcing bars); these should be driven into the ground with only a few
centimeters remaining at the designated points. It is essential that the rods are of equal length and
are driven in to the same depth.
Auxiliary ground 1
Fig. 2-31
Determining of the ground resistance
Example of a DVOR plate ground with 5 x 2 plates, each 1 m
ground resistance of approx. 2 W (good) would be obtained on the basis of the 10 plates, connecting
conductors and assumed terrain conditions (e.g. arable land) in accordance with the formula in Sec
tion 2.6.5.
Measurements are performed as shown in the diagram below:
E
=
1
H
=
2
H
=
1
M
=
2
M
=
3
M
=
Measured value 1:
Measured value 2:
Measured value 3:
Ed. 01.04
approx. 10 m
>50 m
>50 m
Installation ground
Auxiliary ground 1
Auxiliary ground 2
Measured value 1
Measured value 2
Measured value 3
Resistance between installation ground and auxiliary ground 1
Resistance between auxiliary ground 1 and auxiliary ground 2
Resistance between installation ground and auxiliary ground 2
Connection to framework/counterpoise
Grounding plate
DVOR shelter
>50 m
Auxiliary ground 2
2
. The drawing is not to scale. A theoretical
E
M
M
1
3
H
H
1
2
M
2
DVOR 432
Installation
2-35
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