Dry Type Electrical Transformers Voltage Regulation Process

1. Core Principles of Voltage Regulation

• Mandatory Power Off: Never adjust voltage with the transformer energized—high-voltage risks and equipment damage may occur.
• Reliable Grounding: Proper grounding prevents static electricity or residual voltage hazards during operation.
• Refer to Nameplate: Follow the transformer’s factory nameplate for tap position specifications (ensures voltage accuracy).
• Good Contact: Tighten tap connectors to avoid poor contact-induced overheating or discharge.

2. General Voltage Regulation Procedures

1. Power Disconnection & Grounding:
   • Cut off the transformer’s high-voltage input power supply completely.
   • Install a reliable grounding device on the high-voltage side to eliminate residual voltage.
2. Tap Connection Adjustment:
   • Locate the tap terminals (marked on the transformer’s tap block).
   • Move the tap connecting piece to the target tap terminal (align with voltage requirements and nameplate instructions).
   • Tighten the fixing bolts firmly to ensure the tap terminal has stable, low-resistance contact.
3. Final Check & Re-energization:
   • Verify the tap connecting piece is securely fixed, with no loose wires or incorrect connections.
   • Confirm the grounding device is removed before closing the transformer access door.
   • Switch on the power supply only after confirming all operations are correct.

3. Special Voltage Regulation Process for 10/0.4kV Dry-Type Transformers

1. Perform full power-off: Disconnect the low-voltage three-phase five-wire isolating switch and high-voltage circuit breaker.
2. Hang the grounding device on the high-voltage side, then open the transformer’s access door.
3. Locate the 3 tap posts on the transformer—each post is equipped with 6 terminals. Normally, two terminals are connected by a single connecting piece.
4. Adjust the position of the connecting piece on the tap posts (per nameplate guidelines) to achieve the desired voltage.
5. Repeat the final check (connection tightness, no errors) before removing the grounding device and re-energizing.

4. Critical Safety & Operational Notes

• Strictly prohibit live voltage regulation—even momentary energization may cause electric shock or winding damage.
• After adjustment, use a multimeter to test the continuity of tap connections (ensure no open circuits).
• Record the tap position after regulation for future maintenance reference.
• If unsure about tap positions or operation, consult CHH Power’s technical support or refer to the product manual.