Common Issues Leading to Distribution Transformer Burning

There are several common issues that can lead to the burning of distribution transformers:

1.Insurance issues on both sides of the distribution transformer

There is no insurance on both sides of the distribution transformer high and low voltage. Although some have been equipped with drop fuses and horn safety, the fuses are mostly replaced by aluminum or copper wire. As a result, when the low voltage is short-circuited or overloaded, the fuse cannot be blown normally and the transformer is burnt. The high and low fuses of the distribution transformer are not properly configured. The fuse on the transformer is generally over-configured, causing the dry distribution transformer to burn out the transformer when it is heavily overloaded.

2.Rural lighting lines and single-phase power supply issues

Due to the large number of rural lighting lines, most of them use single-phase power supply. Coupled with the randomness and management of the jumper during construction, this results in the partial phase operation of the distribution transformer load. For long-term use, the insulation of a phase coil is aging, causing the transformer to burn out.

3.Tap changer issues

1. Adjust the tap changer privately. Due to the large difference in power load between winter and summer, the voltage changes greatly. Therefore, some rural and enterprise electricians adjust the tap changer without the test adjustment of the power repair department, causing the distribution switch to be out of position, and the contact is poor and burned.

2. The quality of the tap-changer is poor, the structure is unreasonable, the pressure is not enough, the contact is unreliable, the position of the external character wheel is not completely consistent with the actual internal position. This causes the position of the star-shaped moving contact to be incomplete contact, and the misaligned moving and static contacts make the insulation distance between the two taps become small. A short circuit or a discharge to the ground occurs under the potential between the two taps, and the short-circuit current will quickly burn the tap wire and even cause the entire winding to be damaged.

3. Oil seepage issues

   Oil seepage is the most common abnormal appearance of transformers. Since the oil-immersed distribution transformer is filled with oil, there are rubber beads and rubber pads at each joint to prevent oil leakage. After a long period of operation, some rubber beads and rubber pads in the transformer will be cracked and cause oil leakage. This will lead to performance degradation after insulation and moisture, short circuit and burned transformer.

4.Arrester installation issues

Most of the high and low voltage lines of the distribution transformer are introduced by overhead lines. Since the 10kV arrester is not installed, the transformer will be burnt when lightning strikes.

For safety, it is recommended to use a high-quality ZTELEC distribution transformer.