Today we will talk about the reasons and precautions for the short circuit of the secondary side of the current transformer as follows:
1. Normal working principle
Approximate short-circuit state
When the current transformer is working normally, the secondary load impedance is extremely small (close to short circuit). At this time, the magnetomotive force generated by the secondary current is opposite to the magnetomotive force on the primary side, forming a demagnetization effect, making the core magnetic flux stable, and the secondary induced voltage is only a few volts.
2. Analysis of short circuit causes
Abnormal load
When the secondary side load (such as instruments, protection devices) is short-circuited, the secondary current increases sharply, causing the transformer secondary side to short-circuit. This situation may be caused by damage to electrical components or wiring errors.
Improper maintenance operation
If the current transformer needs to be repaired or disassembled, not short-circuiting the secondary side first will cause the core magnetic flux to saturate, generate high voltage (up to thousands of volts), damage the winding insulation and affect the measurement accuracy.
3. Safety and operation specifications
Secondary side open circuit is prohibited
Secondary side open circuit will cause core magnetic flux saturation, high voltage and overheating, which may cause equipment damage or safety accidents.
Short-circuit operation is required
During work, the secondary circuit must be short-circuited with short-circuit turns or short-circuit plates to ensure personal and equipment safety and avoid danger caused by sudden changes in magnetic flux.
4. Precautions
The secondary side should be reliably grounded to prevent induced electric shock.
Select appropriate load parameters to avoid increased errors due to excessive impedance.
Summary: Short circuit on the secondary side of the current transformer is usually caused by abnormal load or improper operation. It must be kept in a short-circuit state for normal operation. Short-circuit treatment must be performed during maintenance to ensure safety.
