tgδ: Loss factor of tested article tgδ value.
CX: Measured capacitance value
V: Applied voltage value
I: Current flowing through the tested article
F1, F2: Testing frequencies
After completing printing, turn off the power switch and the test comes to
an end.
X. Notes for site test
If the test data is obviously unreasonable when using it, it may be caused
by:
1. Poor contact of hook
Hook and tested article should keep in good contact when the hook is
used to connect tested article in site measurement, otherwise the contact point
may discharge and thus lead to wild data fluctuation. Too thick oxide coating of
drainage cable or cable movement caused by wind may lead to poor contact.
2. Poor ground connection
Poor ground connection may cause instrument protection or wild data
fluctuation. Scrape the paint and rust at ground point and guarantee against
any resistance grounding.
3. Direct measurement of CVT or measuring electromagnetic PT with the
method of end shell
Negative value phenomena of dielectric loss may occur when the next
section coupled capacitor of CVT is directly measured. So self-exciting method
will be preferred
In case that negative value of dielectric loss occurs as the result of “T-type
network interference” caused by damp when measuring electromagnetic PT
with the method of end shell, dry the triple petticoat insulator and wiring
terminal block under it. Alternatively, adopt conventional method or increasing
18
