CP SB1 User Manual
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2.2 Operating Principle
The CP SB1 is a transformer switch box whose relays are controlled by the
serial interface of the CPC 100 test system. Potential-free relay contacts control
the AC tap changer of the transformer under test. With the switch box, you can
measure the winding resistance (current up to 6 A) and ratio on three-phase
transformers (output voltage limited to 300 V/150 V). Automatic control of the
OLTC is included. The CP SB1 consists of a relay switching matrix with which
you can conduct automatic testing.
An integrated logic which is controlled by the CPC 100 controls the relays and
the OLTC. The CP SB1 has two outputs to operate the tap changer together with
an optimized "Auto Keep Result" algorithm within the TRTapCheck test card.
Both TRRatio and TRTapCheck test cards can record the results of all three
phases with a single test card. The switch box automatically switches to the next
phase after testing of a phase is completed.
You can conduct the transformer ratio test and the time-consuming tap changer
resistance test over all taps and all three phases without rewiring. For special
measurements and single-phase transformers, the operation mode can be set
to manual. In this case, use banana cables between the connections to the
transformer and the CPC 100 of the CP SB1.
An acoustic signal (intermittent beep) indicates if the discharge is in progress. A
double beep informs the user when a correct connection has been established.
An intermittent beep with a longer interval sounds in case of firmware download.
For the ratio measurement, the voltage is always injected into the high-voltage
side of the transformer. The winding resistance can be measured on the high-
or low-voltage side. Manual mode is possible for both TRTapCheck and
TRRatio.
Note: For detailed information about the ratio measurement, as well as winding
resistance and tap changer test, refer to the CPC 100 User Manual.
2.3 Test Cards
The CP SB1 comprises two test cards: TRRatio to measure the ratio, and
TRTapCheck to test the tap changer of power transformers and the winding
resistance.
Note: The license is indicated on the nameplate with the option "advanced". If
your CP SB1 has a license, the tap check runs in automatic mode by default.
Otherwise (without license), the tap changer has to be tested in manual mode.
Note: For detailed information about further test cards, test procedures and
templates refer to the CPC 100 User Manual.
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General