Guide to Transformer Failures

Transformer damage may lead to unstable power supply in the power system, affecting the normal power consumption of users. In serious cases, it may cause large-scale power outages, causing great inconvenience to social production and peoples lives. In addition, transformer damage may also cause safety accidents such as fires, threatening peoples lives and property.

Oil-immersed transformers

Why would a transformer go bad?

1. Overload: When a transformer operates for a long time at a capacity exceeding its rated capacity, it will cause the winding to overheat, accelerate the aging of the insulation material, and even cause a short circuit failure.

2. Short circuit: A short circuit may occur inside or outside the transformer, which causes an instantaneous increase in current and a great impact on the transformer. In severe cases, the transformer may be burned.

3. Insulation aging: Over time, the insulation material of the transformer will gradually age, which can reduce its insulation performance and increase the risk of damage.

4. No fuse or improper configuration: There is no fuse on both the high and low voltage sides of the transformer or the fuse is improperly configured, which can result in failure to fuse normally during short circuit or overload and burn the transformer.

5. Unbalanced three-phase load: In some rural areas, lighting lines are numerous and messy, most of which use single-phase power supply and jumpers are placed randomly and not managed properly during construction, which causes the transformer load to operate in a phase-biased manner. Long-term use causes the insulation of a phase coil to age and burn the transformer.

6. Poor contact of the tap changer: The tap changer is adjusted privately, which results in the distribution transformer tap changer not being in place and causes poor contact and burning; the tap changer is of poor quality, which causes the star contact position to be incompletely contacted and results in short circuit or discharge to the ground.

Oil-immersed transformers

7. Oil leakage is the most common external abnormality of transformers. Since the transformer body is full of oil, there are rubber beads and rubber pads at each connection to prevent oil leakage. After a long period of operation, some rubber beads and rubber pads in the transformer will age and crack, causing oil leakage. As a result, the insulation performance will deteriorate after being damp, causing discharge short circuit and burning the transformer.

8. Weather reasons. The high and low voltage lines of the transformer are mostly introduced by overhead lines. Due to the failure to put the lightning arrester into operation in time or the failure to install the 10kV lightning arrester, it is easy to be struck by lightning under severe weather conditions such as thunderstorms, resulting in voltage overload, which in turn causes the transformer to burn out.

9. Multi-point grounding of the iron core. Multi-point grounding of the iron core causes abnormal operation of the transformer and damage.

Preventive measures‌

Check the indicators of the transformer regularly to ensure its normal operation;

‌Comply with the correct use and operation specifications‌ to avoid overload, short circuit and other situations;

‌Install lightning arresters during thunderstorm seasons to prevent voltage overload caused by lightning strikes;

‌Prevent moisture from entering the transformer and keep it dry.

The operation of the transformer is closely related to management. But the premise is to choose a transformer with guaranteed quality. You can go to ZTelecgroup to buy a transformer. Before using the transformer, it is necessary to test the transformer. During use, it should be tested regularly. Only in this way can the transformer be effectively avoided from damage.