1, to prevent electric shock: the power transformer power supply is generally through the overhead line, and the overhead line is easy to suffer lightning strikes, the transformer will burn due to breakdown insulation.
2, short-circuit protection to be reliable: transformer coil or load short-circuit, the transformer will withstand a considerable short-circuit current, if the protection system failure or protection set too large, it is possible to burn the transformer. For this reason, a reliable short-circuit protection device must be installed.
3, maintain good grounding: For the low voltage system using protection zero, the neutral point of the low voltage side of the transformer should be directly grounded when the three-phase load is unbalanced, there will be current on the neutral line. When this current is too large and the contact resistance is large, the ground point will appear high temperature, igniting the surrounding combustible material.
4, to prevent overtemperature: transformer operation should monitor the temperature change. If the transformer coil wire is class A insulation, the insulator is mainly paper and cotton yarn, the temperature has a great impact on the insulation and service life, and the insulation life is reduced by about 50% for every 8 ° C rise in temperature. The transformer operates at normal temperature (90 ° C) and has a life of about 20 years; If the temperature rises to 105 ° C, the life span is 7 years. 5 If the temperature rises to 120 ° C, the life span is only two years. Therefore, when the transformer is running, it is necessary to maintain good ventilation and cooling, and forced ventilation can be taken when necessary to achieve the purpose of reducing the temperature rise of the transformer.