Daily safe operation and maintenance of transformers
1: Ensure that the temperature and temperature rise are within the specified range.
When the ambient temperature is 40 degrees Celsius, the limit working temperature of the distribution transformer winding is 105 degrees Celsius, and the upper oil temperature limit temperature of the transformer does not exceed 85 degrees Celsius. If the oil temperature exceeds the allowable value for a long time, it is easy to damage the transformer insulation. In addition, the maximum allowable temperature rise of the winding is 65 degrees Celsius, and the long-term allowable temperature rise of the upper oil temperature is 45 degrees Celsius. As long as the upper oil temperature and temperature rise do not exceed the specified value, the safe operation of the transformer within the specified service life can be guaranteed.
2. Pay attention to the normal overload and accident overload operation capability.
When an accident occurs, in order to ensure continuous power supply to the main electrical equipment and quickly eliminate the fault, the distribution transformer is allowed to be overloaded in a short time. But at this time, it should implement forced air cooling measures to control the upper oil temperature within 95 degrees Celsius, otherwise the insulating oil will deteriorate and eventually damage the transformer.
3.Maintain three-phase load balance.
Pay special attention to the symmetry of the three-phase load on the secondary side. When the three-phase load is severely unbalanced, the voltage of one phase with a heavy load will drop, and the voltage of a phase with a light load will rise, and the deviation will expand to a certain extent, which will threaten the safety of electrical equipment.
4: Ensure that the allowable fluctuation value of the supply voltage does not exceed the rated value.
When the voltage of the transformer is higher than its rated voltage, its excitation voltage will increase, causing the core loss to increase and overheating, and the reactive power will also increase, causing serious distortion of the electromotive force of the primary and secondary windings, increasing the additional motor and circuit At the same time, it causes harmonic resonance in the system, resulting in overvoltage, which will cause harm to the insulation of distribution transformers and other electrical equipment. Therefore, the power supply voltage of a distribution transformer generally does not exceed plus or minus five percent of the rated value.
5.Persist in inspections.
Distribution transformer management staff must perform inspections in accordance with the regulations and carefully check whether the sound is normal, whether there is oil leakage or oil leakage, whether the actual temperature is consistent with the thermometer, whether the insulating sleeve is clean, and the primary and secondary lead wires and contacts Whether the point is firm and overheated, etc. In the process of patrol inspection, it is generally possible to understand the operation status of the equipment according to the instrument, protection device signal light and other equipment. It is also necessary to observe and monitor through various senses, so as to detect potential safety hazards in time, eliminate defects in time, and ensure normal operation.