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other two grounding bodies are:
RB=R1-RA
RC=R3-RA
X. Field Application
1. Application in power system
(1).The measurement of grounding resistance of the tower of
transmission line
Normally, the tower of transmission line connect to the earth to
form multi point grounding system, use ETCR series clamp meter
to clamp the grounding line, can measure the grounding resistance
of the branch circuit.
(2)The measurement of neutral point of transformer
There are two situations for transformer to connect the
grounding line: iterative earth to form multi point grounding resis-
tance; single point grounding measurement for single point groun-
ding.
When measuring, if the meter shows ―L 0.01Ω‖ may because
there are two or more grounding line of tower or transformer con-
nected underground. At this time, should release the redundant
grounding line and just remain one.
(3)The application in power station, power substation
ETCR series clamp meter can use to test the situation of
contact and connect of circuit. With the help of one test line, can be
used to test the connect situation of equipment in station and the
grounding system. Single point grounding measurement is allowed
for the measurement of grounding resistance.
2. Application in telecommunications system
