Power transformer fault causes and treatment methods

A brief analysis of the causes of power transformer faults during operation and the methods to eliminate them is given. The author believes that a correct and reasonable troubleshooting method can promote the normal operation of transformer equipment. In general, transformer failure is mainly caused by power loss in its internal components, circuits, etc., and external human factors or other aspects may also cause its failure. Therefore, when troubleshooting a power transformer, it is necessary to grasp its causes and prescribe the right medicine so as to improve its elimination effect.

First, the analysis and processing of common faults

Transformer oil deterioration

The oil in the transformer was not replaced due to prolonged use, which leaked rainwater and immersed in some moisture. In addition, the oil temperature was often overheated, which could easily lead to deterioration of the oil quality. The deterioration of the oil quality leads to a great influence on the insulation performance of the transformer. This situation is very easy to cause the failure of the transformer. If it is a newly commissioned transformer, its oil color will be light yellow, and after a period of use, the oil color will turn light red. If it is found that the oil begins to darken, in order to prevent current breakdown between the housing and the windings or between the coil windings in this case, sampling tests are performed immediately. After the test, if the oil is qualified, it will continue to be used. If it is not qualified, the insulating oil will be filtered and regenerated to allow the oil to meet the qualification requirements and be used again.

2. The internal sound is abnormal

If the transformer is operating normally, the frequency of the generated electromagnetic hum will be quite stable, and if there is a problem with the operation of the transformer, irregular noise will be occasionally generated in the transformer and abnormal phenomena will be exhibited. Some of the main reasons for this situation are: The transformer is overloaded. In this case, a heavy sound will be generated inside the transformer. When the parts in the transformer are loose, strong and non-uniform noise will be generated during the operation of the transformer. The outermost silicon steel sheet of the transformer core is not clamped. When the transformer is in operation, it will generate vibrations. It will also produce noise; the screw on the top cover of the transformer will loosen, and the transformer will emit abnormal noise during operation; the internal voltage of the transformer When it is too high, the core ground wire will be open circuit or flashover of the shell, the shell and iron core will induce high voltage, and the interior of the transformer will also emit noise; the inside of the transformer will cause poor contact and breakdown, and abnormal noise will be generated due to discharge; When a short circuit or grounding occurs, a large short-circuit current appears in the winding and an abnormal sound is generated. When the transformer generates a harmonic wave and a large-capacity electrical device is connected, a large starting current is generated and an abnormal noise is caused later.

3. Automatic trip fault

During the operation of the transformer, when an automatic trip occurs suddenly, an external inspection is required to find out the reason for the trip. If it is determined after the inspection that the operator is operating improperly or because of an external fault, it can bypass the internal inspection link and perform direct input and power transmission. If a differential protection action has taken place, a thorough and thorough inspection of the equipment in the protected area is required. It is important to note that there are many flammable substances in the transformer, and internal faults may cause fire. If they are not dealt with in time, they may even cause an explosion. There are several factors that may cause the transformer to catch fire: Internal faults cause the transformer's heat sink and casing to crack, and oil spills from the transformer; under the pressure of the oil pillow, the oil in the transformer flows out and then burns on the top of the transformer; Transformer casing damage and flashover. When these accidents occur, the transformer will spontaneously generate protection actions and the circuit breaker will be automatically disconnected. If the circuit breaker is not automatically disconnected for some reason, it must be completed manually, stop the air-conditioning equipment immediately and turn off the power to fight the fire. Transformer extinguishers use foam fire extinguishers and can also use sand to extinguish fires in the event of an emergency.