There are many reasons that can cause current transformers to burn out. Once the root cause is identified, targeted measures can be taken in a timely manner.
Install circuit breakers to avoid branch faults affecting the entire power supply line, especially to ensure that branch circuit breakers can reliably trip.
Connect the current transformer to the circuit breaker to ensure that the circuit breaker and lightning arrester operate correctly in the event of a failure of the transformer.
Strengthen the high-voltage insulation test of the user's current transformers and lightning arrester, and detect the aging degree of the insulation of the transformer and lightning arrester in a timely manner, and replace them in time to avoid power outages caused by the burning of the transformer.
In addition, it is necessary to regularly clean the user's equipment to reduce pollution and avoid insulation reduction.
It is necessary to prevent and reduce the burning of user's current transformers again, which is important for both users and power supply companies.
Causes of current transformer burning out
The secondary of the current transformer is open, producing high voltage, causing the current transformer to burn out.
The current transformer has been used for too long, and the insulation has aged, causing breakdown or discharge, generating overvoltage, and burning out the current transformer due to heating.
The contact surface of the primary connection aluminum bus of the current transformer is heavily oxidized, and the contact resistance is too large, causing heating and burning out the current transformer.
The user is overloaded for a long time, causing the current transformer to heat up and burn out.
Problems with dedicated transformer users' circuit breakers and connections
Generally, 10kV vacuum circuit breakers and SF6 circuit breakers have overcurrent and overload protection. When phase-to-phase short circuit and overload occur, the circuit breaker can trip correctly, and overvoltage is cut off by the installed zinc oxide lightning arrester.
When a single-phase ground fault occurs on the user side, the circuit breaker does not trip, and it is necessary to find the grounding point by pulling out the lower branch of the common line one by one. This will also cause a larger scale power outage in the shared line.
The insulation of the lightning arrester on the user side is aged and cannot effectively prevent overvoltage.
Install circuit breakers to prevent branch problems from affecting the entire feeder, especially to ensure that the circuit breaker on the user side can reliably trip when it is grounded.
Connect the metering current transformer to the circuit breaker at the back to ensure that the circuit breaker and lightning arrester operate correctly when the metering current transformer is faulty.
Strengthen the high-voltage insulation test of the user's high-voltage metering current transformer and lightning arrester, and detect the aging degree of the insulation of the metering current transformer and lightning arrester in a timely manner, and replace them in time to prevent the metering current transformer from burning out and causing power outages.
Regularly clean the user's equipment to reduce pollution and avoid insulation degradation.
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