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XII.Measurement of ground grid resistance by angle
method
Under normal circumstances, the ground impedance test of large-scale grounding
devices adopts the angle arrangement of current and voltage lines. Generally, the
distance dCG between the current post C and the edge of the tested grounding device
should be 4 to 5 times the diagonal length of the ground grid; the length of dPG is similar
to dCG. The ground impedance formula can be modified by the following formula.
In the formula: θ—the angle between the current line and the voltage line;
Z'—the test value of ground impedance.
If the soil resistivity is uniform, an isosceles triangle wiring with equal dPG and dCG can
be used. At this time, θ is about 30°, and the correction formula for dPG=dCG=2D
grounding impedance is still the above formula.
Interface selection: ground network frequency conversion 2A
Summary of Contents for HZDW-DB
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