Grounding resistance measurement of transmission line towers Generally, the grounding of transmission line towers constitutes a multi-point grounding system. Only the ETCR series clamps can be used to clamp the grounding down conductors to measure the grounding resistance of the branch.
Measurement of Neutral Grounding Resistance of Transformer There are two cases of neutral grounding of the transformer: if there is repeated grounding, it will constitute a multi-point grounding system; if there is no repeated grounding, it will be measured by single-point grounding. When measuring, if the clamp shows “L0.01Ω”, there may be more than two grounding down conductors in the same tower or transformer and connected underground. At this point, the other grounding down conductors should be untied, leaving only one grounding down conductor.
The ETCR series of clamps used in power plant substations can test the contact and connection of the circuit. With a test line, you can measure the connection between the station and the ground. The grounding resistance can be measured at a single point ground.
Measurement of the grounding resistance of the floor room The room of the telecommunication system is often located on the upper floor of the building. It is very difficult to measure with a shaker. It is very convenient to test with the ETCR series of clamps. Connect a test lead to the fire hydrant and the grounding pole to be tested (the fire hydrant is installed in the machine room), and then measure the test line with a clamp meter. Clamp resistance = machine room grounding resistance + test line resistance + fire hydrant grounding resistance If the hydrant grounding resistance is small, then: equipment room grounding resistance ≈ clamp resistance value - test line resistance value room, transmission tower grounding resistance measurement room The grounding of the tower usually forms a two-point grounding system, as shown below. If the measured value of the clamp is less than the allowable value of the grounding resistance, the grounding resistance of the equipment room and the tower is acceptable. If the measured value of the clamp is greater than the allowable value, measure it at a single point ground.