One, there is no commercial insurance on both high and low voltage sides of distribution transformers. Although some have already installed fusing cutouts and horn-shaped commercial insurance, the fuse wires are often replaced with aluminum or copper wire, which results in the inability of the fuse to properly melt and burn out the transformer during low voltage short circuits or during load, leading to transformer damage. The high and low fuse wiring on the transformer is not properly equipped. The fuse wires on the transformer commonly exhibit over-sized installations, which consequently causes transformer damage during heavy loads.
Due to the numerous rural lighting fixture routes, most of which are powered by single-phase electrical systems, coupled with the盲目ness of wiring on construction sites and the timeliness of management methods, phase imbalance operations of distribution transformers occur. Prolonged use leads to the脆ification and burning of the transformer's electromagnetic coil insulation layer.
Three: Tap Power Switch
1. Unauthorized adjustment of tap changer switches. Due to the significant difference in electrical load between the two seasons of the year, there is a considerable variation in working voltage. Consequently, some rural and corporate welders, without undergoing experimental adjustment by the power engineering testing unit, have arbitrarily adjusted the tap changer switches, leading to timely failure and burning of the distribution transformer tap changer switches due to loosening.
2. The tap-off power switch has poor quality, an unscientific structure, insufficient working pressure, and unreliable contact. The external gear wheel section does not match the internal specific section, causing the star-type circuit breaker to not touch the location. The displaced moving and stationary contacts reduce the insulation spacing between the two taps, and under the electric potential difference between the two taps, a short circuit fault or ground charging and discharging may occur. The rapid short-circuit capacity can quickly burn the tap winding, and even cause complete winding damage.
Four, oil leakage is a more common surface abnormality in transformers. Since transformers are filled with oil, rubber beads and gaskets are often used at the connection points to prevent oil leakage. Over time, the prolonged operation can cause some rubber beads and gaskets to become brittle and crack, leading to oil leakage. This can result in the insulation layer becoming damp, reducing its properties, causing short-circuit faults during charging and discharging, and ultimately damaging the transformer.
Five, The high and low voltage lines of the distribution transformer are mostly imported from transmission lines, as the zinc oxide surge arresters are not immediately used or the 10kV zinc oxide surge arresters are not installed, leading to transformer damage upon lightning strikes.
Some distribution transformers are not equipped with level one maintenance, or they are equipped with it but have low operability and reliability.
