Transformer cooling control method and transformer cooling system using it

Abstract

The invention relates to a transformer cooling control method for controlling cooling process of a transformer. A rotational speed of a cooling fan for dissipating heat of insulation oil and a rotational speed of an oil-submerged pump for driving the insulation oil to flow are controlled and adjusted according to a parameter expressing a temperature of the insulation oil in the transformer and oil temperature change situation and a parameter expressing the internal temperature change situation in the transformer and thermal state change situation. A transformer cooling system employing the transformer cooling control method comprises a temperature sensor, a current transformer, a controller, a working power supply, the cooling fan, the oil-submerged pump and a communication interface. The rotational speeds of the cooling fan and the oil-submerged pump are controlled and adjusted by taking the oil temperature and the thermal state as basis, more fine control can be achieved, the temperature in a wide range is adapted, active and flexible control on the transformer during the cooling process is achieved, and the running reliability of the transformer is improved.

Description

technical field [0001] The invention belongs to the technical field of electric power industry control, and in particular relates to a method for controlling the cooling process of a transformer and a transformer cooling system for realizing the method. Background technique [0002] With the development of the power industry, the capacity of the power grid continues to increase, and the capacity of the transformer, which is the core equipment for power transmission in the power grid, is also increasing. The introduction of various simulation and other advanced design tools and software, comprehensive transportation weight, volume and dimensions Constrained by many factors, large-capacity transformers are gradually approaching the limit of industrial manufacturing, and any defects in the manufacturing process and improper operation methods will affect the reliability of their operation. [0003] During the operation of the transformer, in addition to the heating loss caused b...

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Problems solved by technology

[0008] There is a sudden increase or sharp decrease in the load current of the transformer, but the change of the oil temperature and body temperature has a hysteresis. With the increase of the transformer capacity, the oil circuit becomes longer, and the cooling power of the cooler is greater, but it is difficult to adjust Larger, if the cooling effect is regulated solely according to the change of the load current, the sudden change of temperature will easily lead to local overcooling or too low temperature. Because the temperature affects the water-soluble ability of the oil, the microscopic moisture distribution is uneven, and even It leads to the precipitation of local water supersaturation, forming suspended water droplets; while the single regulation based on oil temperature is due to the hysteresis of temperature. After the temperature reaches the upper limit, the fan starts, the cooling intensity increases, and the temperature drops rapidly; when the temperature reaches the lower limit Finally, the fan stops, but due to the heat capacity of the internal core, the oil temperature rises, so there must be a suitable interval between the upper and lower limits of the start and stop, to avoid frequent start and stop of the fan, which will cause the oil temperature to fluctuate more. Large, it is easy to cause the local temperature inside the transformer to be too high, and the oil temperature fluctuates. It is easy to lead to the enrichment of local moisture and affect the service life of transformer insulation materials

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