Vacuum Circuit Breaker (VCB) Commissioning Test Report

This document gives a comprehensive technical test report template and guidance for Vacuum Circuit Breakers (VCBs) used in medium voltage power systems. 

It covers visual inspection, mechanical checks, insulation tests, contact resistance, timing tests, vacuum integrity, primary and secondary injection, and final acceptance criteria.

Scope

This report provides a complete commissioning and acceptance record for medium-voltage vacuum circuit breakers.

Recommended Test Instruments

• 5 kV Insulation Resistance Tester,

• Micro-ohmmeter (100 A or higher),

• Circuit Breaker Analyzer,

• Primary Injection Test Set,

• Secondary Injection Relay Test Kit,

• Digital Multimeter,

• Torque Wrench and

• Thermal Camera (optional).

Equipment Information

Record manufacturer, model, serial number, rated voltage, rated current, short-circuit breaking capacity, panel identification, installation location, commissioning date, ambient temperature, humidity, and applicable standards (IEC 62271-100 / IEEE C37).

Pre-Test Safety

Isolate the breaker, apply lockout/tagout, verify absence of voltage, discharge stored energy, wear appropriate PPE and ensure the breaker is in a safe condition before testing.

1). Visual Inspection

Inspect insulation, bushings, shutters, operating mechanism, wiring, auxiliary contacts, earthing, cleanliness, corrosion, loose hardware, and nameplate details.

Test Equipment	Standard/Limit	Measured Value	Result	Remarks
1).

2). Mechanical Operation Test

Perform manual and electrical OPEN/CLOSE operations. Verify smooth operation, charging mechanism, anti-pumping, trip-free function, operation counter, and spring charging motor.

Test Equipment	Standard/Limit	Measured Value	Result	Remarks
1).

3). Insulation Resistance Test

IR test is used to ensure insulation resistance phase-to-phase & phase-to-earth using a 5 kV insulation resistance tester. 

Record temperature-corrected values and compare with manufacturer recommendations.

Test Equipment	Standard/Limit	Measured Value	Result	Remarks
1).

4). Contact Resistance Test

Contact Resistance Test measure each pole using a calibrated microohmmeter (µΩ) with at least 100A DC test current. 

Compare all poles for uniformity & verify all the compliance with the manufacturer limits.

Test Equipment	Standard/Limit	Measured Value	Result	Remarks
1).

5). Timing Test

Measure opening time, closing time, contact bounce, pole discrepancy and synchronization using a circuit breaker analyzer. 

Compare results with factory specifications.

Test Equipment	Standard/Limit	Measured Value	Result	Remarks
1).

6). Vacuum Integrity

Verify and check the health of vacuum interrupter utilizing the approved vacuum bottle test method which is recommended by the manufacturer. 

Do not perform any tests exceeding manufacturer limits.

7). Functional Tests

Check trip coil, close coil, undervoltage release, auxiliary contacts, spring charging motor, interlocks, remote/local control, SCADA indications, alarms and annunciation.

8). Primary Injection Test

Primary injection test used to inject current via the primary circuit to verify current path integrity, CT polarity, relay operation & trip functionality.

9). Secondary Injection Test

Inject test signals into protection relays to verify relay settings, timing, alarms and breaker trip operation.

Acceptance Criteria

All measured values shall be within manufacturer tolerances. No abnormal noise, excessive contact resistance, insulation deterioration, timing deviation (or) functional failure shall be observed.

Typical Test Record Table

Include columns for Test Item, Standard/Limit, Measured Value, Result (Pass/Fail), Remarks, Test Instrument, Calibration Due Date.

Blank Commissioning Test Sheet

Parameter	Limit	Measured	Pass/Fail	Remarks
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15).

Engineer Signature: ____________________    

Client Signature: ____________________

Approval

Tested By
Reviewed By
Approved By
Date

Conclusion

State whether the breaker is acceptable for service, requires corrective maintenance, or should remain out of service until defects are rectified.