A DC kick test can verify current-transformer polarity on the 230 kV ABB SF6 breaker described in the evidence. Apply a battery briefly to the CT primary circuit and observe an analog voltmeter on the secondary. The initial meter deflection when closing the battery circuit is the primary result; the opening deflection reverses direction and may be harder to see because it is shorter.
Define the Test Boundary
Perform this test only with the breaker and CT primary circuit de-energized, isolated, and controlled under the site electrical-safety procedure. Confirm that no other source can energize the CT and that the secondary connections under test are identified before applying the battery.
The evidence does not provide CT terminal markings, ratio, internal wiring, battery voltage, or an ABB-specific connection diagram. Obtain the applicable breaker and CT drawings before assigning a physical terminal as the polarity terminal; the kick test establishes relative polarity only when the battery leads, voltmeter leads, and terminal identities are recorded.
Connect the Battery and Analog Voltmeter
| Test element | Connection or requirement | Purpose |
|---|---|---|
| Battery | Connect for momentary DC application through the CT primary path | Produces the changing flux required for a secondary voltage kick |
| Analog voltmeter | Connect across the CT secondary with lead polarity recorded | Shows the direction of the transient deflection |
| Documentation | Record primary lead polarity, secondary lead polarity, and terminal labels | Makes the observed kick usable as a polarity result |
Do not infer the required meter range or battery rating from this evidence; those values are unspecified. Select equipment and connections through the approved test procedure and applicable manufacturer documentation.
Perform the DC Kick Test
- Verify the CT is de-energized and identify the primary and secondary terminals from the project drawings.
- Connect the analog voltmeter across the secondary and record which secondary terminal is connected to the meter-positive lead.
- Connect the battery leads to the primary test path and record which primary terminal receives battery positive.
- Momentarily close the battery circuit while watching the meter. Record the direction of the first deflection.
- Open the battery circuit and observe the reverse deflection if visible. The opening indication may be shorter and more difficult to observe.
- Repeat the make operation to confirm that the initial deflection is consistent before accepting the result.
Interpret and Verify Polarity
With the recorded lead arrangement, the closing deflection has the same polarity sense as the applied battery connection. Opening the circuit produces the opposite deflection. Use the closing kick as the primary observation because the opening kick may be too brief to read reliably.
Compare the result with the breaker wiring drawings and required protection scheme before placing the circuit in service. A repeatable kick confirms relative CT polarity for the tested terminals; it does not by itself verify CT ratio, insulation, phase assignment, secondary continuity beyond the test path, or the complete protection wiring.
Frequently Asked Questions
Can I test breaker CT polarity with a battery and analog voltmeter?
Yes. With the equipment de-energized, briefly apply the battery through the CT primary path and observe the analog voltmeter connected across the secondary.
Which meter movement determines CT polarity during a battery test?
Use the initial deflection when the battery circuit closes. The deflection when the circuit opens is opposite and may be shorter and harder to observe.
Does a DC kick test prove the breaker CT is completely serviceable?
No. It verifies relative polarity for the recorded connections but does not establish CT ratio, insulation condition, phase assignment, or correctness of the complete protection circuit.