Emergency Handling of Current Transformer Installation Errors

I. Immediate Power Disconnection and Warning Setup

Upon discovering an installation error (such as reverse meter rotation, protection tripping, or negative meter reading), immediately disconnect the primary power supply to prevent the accident from escalating.

Hang a "Do Not Close, People Working" warning sign on the switchgear to ensure operational safety.

II. Emergency Correction for Different Error Types

1. Secondary Side Open Circuit (Most Urgent)

Risk: High voltage has been generated, which may break down insulation or endanger personnel.

Handling: After confirming power disconnection, use insulated tools to check the secondary circuit;

If loose terminals or an open circuit are found, short-circuit S1-S2 with jumper wires;

Retighten all terminals to ensure reliable contact.

2. Reversed Polarity or Direction

Troubleshooting:
Check if P1 is facing the power supply side and P2 is facing the load.
If the primary side is reversed, adjust the primary cable connection.
If the secondary side S1/S2 is reversed, swap the connections of S1 and S2 (recommended method).
After correction, verify the polarity using a DC method or a polarity tester.

3. Grounding Error (Multiple Grounding Points or No Grounding)

Troubleshooting:
Check if S2 is reliably grounded at one point.
Remove all additional grounding points, leaving only one connected to the dedicated grounding copper busbar.
Do not connect the grounding wire to the cabinet bolts.

4. Improper Primary Side Installation (Eccentricity, Loosening)

Troubleshooting:
Readjust the through-core conductor to ensure vertical centering.
When multiple cables are through-core, arrange them symmetrically in three phases.
Reclose the open-type CT and tighten the screws.

III. Verification Required Before Restoration

Polarity Test: Use a DC method or a transformer polarity tester to confirm correct polarity.

Circuit Check: Confirm no open circuits, no short circuits, and a single, reliable ground connection.

No-Load Power-On Test: First, energize without load and observe whether the instruments function normally.

Load Verification: Gradually increase the load and use a clamp meter to compare the primary and secondary current ratios to ensure they match the turns ratio.

⚠️ It is strictly forbidden to disconnect the secondary circuit without shorting S1-S2 to prevent high-voltage hazards.