Transformer Commissioning Checklist

Here’s a detailed Transformer Commissioning Checklist designed for use with eAuditor Audits & Inspections. This checklist covers all critical steps, from pre-installation to post-energization tests, ensuring proper and safe commissioning of a transformer.

Transformer Commissioning Checklist

1. General Information

• Project Name/Location:
• Transformer Manufacturer:
• Serial Number:
• Model Number:
• Voltage Rating:
• Power Rating:
• Type of Transformer: (e.g., Power, Distribution, Dry, Oil, etc.)
• Date of Commissioning:
• Commissioning Team:
• Client Representative:

2. Pre-Commissioning Preparation

• Documentation Check:
  • Transformer manual and manufacturer’s instructions available.
  • As-built drawings reviewed.
  • Installation and test procedures outlined and agreed upon.
  • Approved test plans available.
• Safety & Environment:
  • Proper site access for equipment and personnel.
  • Adequate grounding of transformer and associated equipment.
  • Safety and warning signs posted.
  • Ensure environmental protection measures (spill containment for oil, etc.).
• Equipment Inspection:
  • Transformer visually inspected for physical damage.
  • Confirm all components delivered are as per specification (e.g., bushings, tap changers, radiators, fans).
  • Verify nameplate information matches the purchase order.

3. Transformer Installation Checks

• Positioning & Foundation:
  • Ensure transformer is positioned according to the design layout.
  • Verify correct alignment and leveling.
  • Ensure proper vibration damping measures are in place.
• Grounding:
  • Verify the transformer is adequately grounded.
  • Confirm that neutral grounding is installed as per the design.
  • Test the continuity of grounding connections.
• Terminations & Connections:
  • Verify that high-voltage (HV) and low-voltage (LV) cables are correctly terminated.
  • Check that all connections (HV, LV, neutral, ground) are secure and in accordance with drawings.
  • Verify the correct polarity and phasing of connections.
• Cooling System:
  • Confirm that cooling fans, radiators, and oil pumps (if applicable) are properly installed and secured.
  • Ensure proper connections for cooling system electrical and control circuits.

4. Oil-Filled Transformer Specific Checks (if applicable)

• Oil Levels and Quality:
  • Verify correct oil level in the conservator tank.
  • Perform oil sampling and testing (dielectric strength, moisture content, DGA – dissolved gas analysis).
  • Confirm oil is free of contaminants.
• Breather System:
  • Ensure silica gel in the breather is fresh and functioning.
  • Check the correct connection of the breather to the conservator tank.
• Pressure Relief Devices:
  • Verify pressure relief device is correctly installed and functional.
  • Test alarm/trip signals connected to the pressure relief system.

5. Pre-Energization Electrical Testing

• Insulation Resistance Testing (Megger Test):
  • Test insulation resistance between winding phases, between windings, and between winding and ground.
  • Record results for comparison against manufacturer’s standards.
• Transformer Turns Ratio (TTR) Test:
  • Perform TTR test to verify proper winding ratios.
  • Confirm results are within acceptable limits.
• Winding Resistance Test:
  • Measure and record winding resistances of all windings.
  • Ensure resistances match design specifications.
• SFRA (Sweep Frequency Response Analysis):
  • Conduct SFRA test to assess the mechanical integrity of the transformer core and windings.
• Power Factor/Dissipation Factor Testing (Tan Delta):
  • Test insulation power factor for all windings to assess insulation condition.
• Polarity and Phase Verification:
  • Verify correct polarity of windings.
  • Perform phase verification test to confirm correct phase connections.

6. Protection and Control Systems

• Relays & Protection Settings:
  • Verify the protection relays (overcurrent, differential, etc.) are correctly installed and settings are as per design.
  • Test the functionality of all relays by simulating faults.
• Buchholz Relay (for Oil-Filled Transformers):
  • Verify Buchholz relay functionality.
  • Test for proper connection to the alarm/trip circuit.
• On-Load Tap Changer (OLTC):
  • Confirm correct operation of the OLTC.
  • Check OLTC control panel and ensure proper communication with SCADA/DCS.
  • Perform OLTC step change test.
• Cooling System Operation:
  • Test the operation of cooling fans and oil pumps under normal and emergency conditions.
  • Verify temperature monitoring and control circuits (RTDs, thermocouples, etc.).

7. Grounding System Tests

• Ground Resistance Test:
  • Perform ground resistance testing of the transformer’s grounding system.
  • Ensure resistance is within acceptable limits.
• Continuity Test:
  • Perform continuity tests on all grounding connections.
  • Verify all metal parts (tank, radiators, etc.) are properly bonded.

8. Final Pre-Energization Checks

• Physical Inspection:
  • Conduct a final inspection to ensure no tools or foreign materials are left in or around the transformer.
  • Ensure all covers and access points are securely closed.
• Communication Systems:
  • Confirm communication between transformer and control system (SCADA, RTUs).
  • Verify proper signal transmission for alarms, status indications, and measurements.
• Final Review of Test Results:
  • Review and confirm all pre-energization test results are within acceptable ranges.

9. Energization Procedure

• Approval to Energize:
  • Obtain formal approval from relevant stakeholders to energize.
  • Ensure all personnel are cleared from the vicinity.
• Initial Energization:
  • Apply voltage gradually (if applicable).
  • Monitor for unusual noises, vibrations, or other abnormal conditions.
  • Ensure cooling system operates as expected under load.

10. Post-Energization Checks

• Voltage and Load Readings:
  • Record voltage levels on HV and LV sides.
  • Monitor the transformer under load for 24–48 hours.
• Temperature Monitoring:
  • Monitor oil and winding temperatures.
  • Ensure the cooling system adjusts according to the load and temperature rise.
• Buchholz Relay and Protection Alarms:
  • Monitor for any abnormal alarms during initial operation.
  • Confirm protection relays are functioning as designed.

11. Completion and Sign-Off

• Commissioning Completed By:
  • Name/Signature:
  • Date:
• Reviewed and Approved By:
  • Name/Signature:
  • Date:
• Client Representative:
  • Name/Signature:
  • Date:

How to Use Transformer Commissioning Checklist in eAuditor Audits & Inspections

1. Create a Template: In eAuditor Audits & Inspections, create a new template using Transformer Commissioning Checklist structure provided above or use existing Transformer Commissioning Checklist from eAuditor.
2. Customize Fields: Modify the checklist to suit the specific transformer type, equipment, and site conditions. You can add or remove fields as needed.
3. Use Checkboxes & Input Fields: Include checkboxes for each item, and input fields for test results, inspector comments, and signatures.
4. Add Photos: Take photos during inspections and tests and attach them directly to the checklist.
5. Generate Reports: After completing the checklist, use eAuditor Audits & Inspection’s reporting feature to generate PDF reports and share them with the team and client.

This checklist ensures that all necessary steps in the commissioning of a transformer are covered, promoting safe and effective operation from the start.