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7.3.2 test methods
All grounding lead lines of the measured tower are removed and short connected with
metal as the test lead of the grounding device. A test instrument is connected to the
circuit formed by the grounding device, the grounding device tower, the lightning
protection line, the remote multistage tower and its grounding device and the earth, as
shown in figure 8, which generates the test current and measures the Z’tj. of the
grounding impedance Since the parallel effect of the grounding impedance of the remote
multistage tower grounding device, the Z’tj is larger than and similar to the grounding
impedance of the grounding device of the measured tower Ztj, which is acceptable in the
test of the grounding impedance of the tower.
W of lightning lines directly connected to multistage towers
Grounding impedance P10 tester o 2
Grounding device for pole tower/
Fig .8 Schematic diagram of grounding impedance test of tower by circuit impedanc.
The measured value of Z’tj sentence is too large or too small (if greater than 502 or less
than 2 Q), or more than the empirical value, the three-pole method is used to verify.
Summary of Contents for HZDW-DB
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