Transformer Partial Discharge
Partial discharge in transformers occurs within the insulation of transformers and other high-voltage equipment due to various reasons. Under a certain external voltage, localized and repetitive breakdown and extinction phenomena happen inside the equipment. This partial discharge occurs in one or several small spaces, with minimal discharge energy. The existence of partial discharge does not affect the short-term insulation strength of electrical equipment.
If partial discharge occurs in a transformer's irreversible insulation under operating voltage, the weak discharge energy and the resulting adverse effects can gradually damage the insulation, eventually leading to complete breakdown over time. The hazards associated with this phenomenon have gradually been recognized.
In the early 1980s, research began in China on the causes of partial discharge in transformers and other high-voltage equipment, as well as measurement methods. By the mid-1980s, the research results were applied to transformers and other high-voltage equipment. Currently, the requirement for partial discharge is gradually being extended from high-voltage products to lower-voltage products, with a clear trend toward decreasing allowable apparent discharge levels. This requirement primarily aims to enhance the operational reliability of electrical equipment.
Manufacturers of electrical equipment are continuously striving to improve design and manufacturing processes and to enhance production environment conditions. Currently, in high-voltage transformers, both high-voltage and medium-voltage apparent discharge levels can be maintained below 100 pC.
