How to maintain oil-immersed transformer

Oil-immersed transformer is one of the common and important equipment in power system, which is widely used in power transmission and distribution system. It carries out cooling and insulation protection through insulating oil to ensure the safe and stable operation of the equipment. However, it is very important to maintain the oil-immersed transformer scientifically and systematically because of its long-term operation in high voltage and high temperature environment. This paper will introduce the daily maintenance methods and precautions of oil-immersed transformer in detail.

First, regular inspections and inspections

The daily inspection of oil-immersed transformer is the first line of defense to ensure its normal operation. The operation and maintenance personnel shall regularly inspect the appearance of the transformer to observe whether there is oil leakage, oil leakage, abnormal oil level, shell deformation or corrosion, etc. At the same time, pay attention to whether there is abnormal sound or odor when the transformer is running. In addition, the infrared thermometer should be used to measure the temperature of each part of the transformer to prevent faults caused by local overheating.

Second, the oil detection and maintenance

Transformer oil is the key factor to realize insulation and cooling functions. The transformer oil is sampled and tested regularly, and the main testing items include: breakdown voltage, moisture content, acid value, dielectric loss and other indicators. If the oil quality is found to decrease, it should be filtered or replaced in time. It is generally recommended to conduct a comprehensive oil quality analysis at least once a year to ensure that the oil products meet the national standards.

Third, electrical performance testing

In order to ensure that the internal insulation of the transformer is in good condition, preventive tests should be carried out regularly, such as insulation resistance test, dielectric loss tangent test, winding DC resistance test and variable ratio test. These tests are helpful to discover the potential defects inside the transformer in time, such as turn-to-turn short circuit and insulation aging.

Fourth, the maintenance of the cooling system

The cooling methods of oil-immersed transformer mainly include natural oil circulation cooling (ONAN) and forced oil circulation cooling (ONAF or OFAF). Cooling systems such as radiators, fans, oil pumps, etc. should be regularly checked for their running status and kept clean to avoid overheating failure caused by poor heat dissipation.

V. Environmental Management and Safety Protection

The place where the transformer is installed should be well ventilated and away from inflammable and explosive materials. Fire prevention and isolation measures should be set around the transformer, and sufficient fire fighting equipment should be equipped. In addition, measures should be taken to prevent moisture, dust and small animals from affecting the normal operation of the transformer.

VI. Records and Archives Management

Establish perfect equipment files and operation records, including patrol records, inspection reports, maintenance records and other information. These data are not only helpful to master the running status of equipment, but also provide important reference for future fault diagnosis and maintenance.

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To sum up, the maintenance of oil-immersed transformers involves many aspects, including both daily inspections and professional inspection and maintenance. Only through scientific and standardized management and maintenance can the service life of transformers be effectively extended and the safe and stable operation of power system be guaranteed. Therefore, the relevant operation and maintenance personnel should attach great importance to the maintenance of transformers, so as to nip in the bud and ensure the safe and efficient operation of the power grid.