What phenomena occur when the secondary side of a current transformer is open-circuited?

1. High Voltage: After the circuit is open, the magnetic flux of the iron core increases sharply, which may induce a voltage of several thousand volts on the secondary side, breaking down the insulation or causing an electric arc.

2. Abnormal Sounds: Accompanied by a "squeaking" discharge sound and vibration, and in severe cases, a "crackling" discharge sound.

3. Instrument Abnormalities: The ammeter and wattmeter indicate zero, and the energy meter stops rotating.

4. Equipment Overheating: Iron core saturation leads to increased eddy current losses, causing the casing temperature to rise, which may burn out the current transformer.

5. System Risks: Relay protection malfunctions, inaccurate energy metering, and even fire or explosion.

6. Handling Recommendations: Immediately disconnect the power, short-circuit the secondary side with a shorting bar, and avoid direct contact with the open circuit point.