09,22,2026 22 views
With the rapid development of China's power system, the requirements for the reliability and safety of system operation are increasing day by day. Power transformer is one of the important electrical equipment in the power system, and its safe and stable operation is particularly crucial for the safe and stable operation of the power system. The operational reliability of power transformers largely depends on the reliability of their insulation. According to statistics, between 2000 and 2004, power transformer failures accounted for 45% of high-voltage equipment accidents, and insulation failures were the main cause affecting the normal operation of transformers. Therefore, improving online monitoring of the insulation condition of power transformers is of great significance for ensuring the safe and stable operation of the power system.
Power transformers are one of the key large-scale equipment in the power system, and their faults are mainly caused by factors such as lightning overvoltage, operational overvoltage, and short-term high current. At the same time, the initial insulation defects inside the transformer are also an important cause of faults. The internal insulation structure of transformers is mainly composed of oil paper composite insulation, and partial discharge is an important factor that promotes the aging and development of oil paper insulation to breakdown. Therefore, by monitoring the partial discharge inside the transformer, the insulation status of the transformer can be accurately determined.
Partial discharge refers to the electrical discharge phenomenon in which a local area of insulating material is broken down under the action of an electric field. The uneven insulation strength in certain areas inside or on the surface of an insulator leads to severe distortion of the electric field in that area, and the electric field strength will be higher than the average electric field strength. Therefore, discharge will occur first in such areas, while other areas still maintain their insulation characteristics, forming partial discharge. The partial discharge that occurs near a conductor surrounded by gas is called corona; Partial discharge occurring on the surface of an insulator is called surface partial discharge; Partial discharge occurring inside an insulator is called internal partial discharge.
Partial discharge is both an important factor and a significant symptom of insulation degradation in transformers. Therefore, online monitoring of partial discharge inside transformers can timely and effectively detect inherent insulation defects and local hazards caused by long-term factors.
