Why do marine transformers burn out?
Why do marine transformers burn out?
The phenomenon of marine transformer burning is generally that the temperature rise of the marine transformer is too high or the coil insulation is damaged. The temperature before the burning is not high, which does not mean that the temperature of some parts is not high. The overload of the marine transformer and the small temperature rise design margin may lead to some high temperatures, and then It will cause the failure of the marine transformer and cause a burnout accident.
The reasons for the burning of marine transformers:
(1) There are no fuses on the high and low voltage sides of the marine transformer.
(2) Improper configuration of high and low voltage fuses of marine transformers.
(3) Rural electricity is generally single-phase power supply, and the uneven distribution of capacity leads to overloaded use. Then it is long-term overloaded use without maintenance and maintenance.
(4) Marine transformer tap changer:
(5) Regulate the tap changer without permission, so that the distribution tap changer is not in place, and the contact is bad and burned.
(6) The quality of the tap changer is poor, causing incomplete contact of the star contact position, short circuit or ground discharge.
(7) The iron core is grounded at multiple points.
(8) When the low-voltage side of the marine transformer is grounded and the phases are short-circuited, a short-circuit current that is 20-30 times higher than the rated current will be generated. Such a large current acts on the high-voltage winding, and the coil will generate a lot of mechanical stress. This mechanical stress will cause the coil to shrink. After the short-circuit fault is removed, the stress will also disappear. If the coil is repeatedly subjected to mechanical stress, its insulating rubber beads, rubber pads, etc. will be loose and scattered; Ring distortion or cracking. In addition, high temperature will also be generated, which will cause the marine transformer to burn out in a very short time.
