Omicron CPC 100 Reference Manual

CPC 100 V1.41
6 - 18
TRTapCheck (for OLTC)
Use the TRTapCheck test card to measure the winding resistance of the
individual taps of a power transformer’s tap changer, and to check whether the
on-load tap changer (OLTC) switches without interruption.
CPC 100 injects a constant current from the 6A DC output into the power
transformer and the current is led via the IAC/DC input for measurement.
Alternatively, the current injected from the 400A DC output is measured
internally. From this current value and the voltage measured by the V DC input
(see Figure 12), the winding resistance is calculated.
In the moment the tap is changed, the IAC/DC measuring input detects the
sudden, very short drop of the current flow. A properly working tab change
differs from a malfunctioning one, for example, an interruption during the
change, by the magnitude of the ripple and slope values. An interruption will
result in much higher ripple and slope values than a properly functioning tab
change.
The ripple and slope values are indicated at the TRTapCheck test card’s
measurement table (refer to Figure 13).

Omicron CPC 100 Specifications

General

Brand	Omicron
Model	CPC 100
Category	Test Equipment
Language	English