Partial discharge phenomenon and preventive measures of power transformers

Partial discharge phenomenon and preventive measures of power transformers

1、 Overview of Partial Discharge Phenomenon

Partial discharge in power transformers refers to the electrical discharge phenomenon that occurs within the insulation material or in a localized area on the surface of the transformer. This type of discharge usually does not immediately cause insulation penetration breakdown, but long-term presence can accelerate the aging of insulation materials, ultimately leading to insulation damage and affecting the safe operation of transformers.

2、 Reasons for partial discharge generation

1. Aging of insulation materials: During long-term operation of transformers, insulation materials will gradually age due to factors such as heat, mechanical stress, and chemical corrosion, resulting in a decrease in dielectric strength and easy occurrence of partial discharge.

2. Wet environment: Wet environment can increase the conductivity of insulation materials, thereby increasing the probability of partial discharge.

3. Impurities and bubbles: Defects such as impurities and bubbles that exist during the manufacturing or installation process of insulation materials can become the starting point of partial discharge.

4. Uneven electric field: The internal electric field distribution of transformers is uneven, especially at the contact surfaces between insulation joints, transformer windings, and iron cores, which can easily lead to local electric field concentration and discharge.

5. Frequent load fluctuations: Frequent load fluctuations can cause instantaneous changes in current, leading to changes in electric field and increasing the risk of partial discharge.

3、 Preventive measures

1. Regular inspection and maintenance: Use partial discharge detectors to regularly inspect transformers, promptly identify and address potential partial discharge issues. At the same time, develop corresponding maintenance plans based on the detection data.

2. Replace insulation materials: For severely aged insulation materials, they should be replaced in a timely manner and necessary moisture-proof measures should be taken.

3. Optimization design: In the design and manufacturing process of transformers, efforts should be made to avoid uneven electric fields. By optimizing the insulation structure and materials, the risk of partial discharge can be reduced.

4. Load management: Reasonably arrange the load of transformers, avoid frequent load fluctuations, and reduce the risk of partial discharge caused by load changes.

5. Use high-quality materials and improve the level of craftsmanship: Select high-quality insulation materials and improve the level of craftsmanship in the manufacturing process to reduce the occurrence of defects such as bubbles and impurities.

6. Training and awareness raising: Regularly train power system personnel to enhance their understanding and ability to respond to partial discharge.

In summary, understanding the causes and preventive measures of partial discharge in power transformers is of great significance for ensuring the stable operation of the power system. By regularly detecting and maintaining, replacing insulation materials, optimizing design, load management, using high-quality materials, and improving process level, the risk of partial discharge can be effectively reduced, and the operational reliability of transformers can be improved.