The Method of Determining the Saturation Point of Current Transformer and the Measures to Prevent Burnout
In order to check whether the current transformer will be full when the current is too large and affect the correctness of the maintenance action, the direct experimental method is to carry a practical load on the secondary side and apply current from the primary side. In addition, the transformer factory can also test the full point of the current transformer through the volt-ampere characteristic experiment.
The current transformer is full because the core magnetic flux density is too large to form the full current of the current transformer. The experimental method for the volt-ampere characteristics of the transformer factory is: the original side opens a circuit, and the current is passed in from the secondary side to measure the voltage drop on the secondary side winding. Because the original side of the current transformer is open, there is no demagnetization effect of the original side current, and the iron core is simple and full under the small current effect. Therefore, the volt-ampere characteristic experiment does not need to add a large current and is relatively simple to complete on site.
There are many reasons for the burning of current transformers, such as the secondary open circuit of the current transformer, which generates high voltage, which causes the current transformer to burn out; if the use time is too long, the insulation aging, partial breakdown or discharge occurs, overvoltage occurs, and current The transformer is heated and burned out; the touch surface of the current transformer connected to the aluminum row at a time is too oxidized, the touch resistance is too large, and the heating causes the current transformer to burn out; the user overloads for a long time and causes the current transformer to heat and burn out.
To prevent the current transformer from burning out, it is important to install a circuit breaker to prevent branch faults from power outages involving the entire line, especially to ensure that the branch circuit breakers can reliably trip. Then connect the current transformer to the back of the circuit breaker to ensure that the circuit breaker and arrester act correctly when the transformer is faulty.
It is also necessary to strengthen the user’s current transformer and arrester high-voltage insulation experiment, find the insulation aging degree of the transformer and arrester as soon as possible, and replace it in time to prevent the occurrence of a power outage caused by the burning of the transformer. It is to clean users’ equipment regularly to reduce pollution and prevent insulation degradation.
When using a current transformer, carefully check whether the secondary circuit is open, whether the touch resistance is too large, and it is important not to overload it. In addition, the current transformer should be protected and maintained. If the insulation is found to be aging, it should be replaced in time, and it should be cleaned regularly to reduce pollution. Only in this way can the current transformer be used more safely and has a longer service life.