To eliminate the stray capacitances, you have to connect the unwanted capacitances to this point.
V-potential terminal is also provided on instrument panel (See chapter 7.2 on page 38,
10:Guard(V))
1
.
The following figure shows an example of eliminating a stray capacitance of one bushing, which is
caused by bushing surface leakage current. By using a conducting collar which is placed and
tightened on bushing surface near the tank (not touching) and connected to guard, leakage current
of bushing guarded will not measure.
The shields of the measurement cables are also connected to this V-potential. Do not use
unshielded measurement cables!
By selecting the different test modes, all combinations of measurements according the ANSI/IEEE
Standard 62 can be measured without any rewiring.
1 The CAPO 2.5 has no special terminal for the V-potential. But you can use the metal-housing of the plugs (HV, Input A, Input B),
they have the V-potential.
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