Corona can occur in switchgear 2000V or greater, which could potentially lead to flashover, especially in enclosed switchgear, causing enormous damage and personal injury. This results from ionized air or ozone caused by damaged insulation, contamination, and faulty design. The byproducts of corona, nitric acid, and carbon cause a continuous decay of insulation, making the situation highly unpredictable. With ultrasound inspection, corona can be detected and remedied before serious results occur.
What types of problems will an ultrasound inspection detect?
Arcing occurs in all voltages. All forms, including tracking, affect the quality of power. In addition, arcing through air or through bulk insulation destroys electrical power equipment.
Occurs through damaged insulation material when conductors of 1000V or more begin to ionize the air, forming ozone (O3). Ozone will conduct current and can form a direct path to ground, resulting in catastrophic results, especially in enclosed switchgear. Corona also produces nitrogen exides, which form nitric acid when combined with moisture. This acid further destroys the insulating material as well as metal components, causing possible thermal problems.
Often referred to as “baby arcing,” tracking follows the path of damaged or dirty insulation across component surfaces. Tracking occurs most often in medium to high voltage equipment (1-kV or greater)
Occurs inside electrical components such as transformers and insulated bus bars. It is affected by and causes insulation deterioration.
Can be indicative of serious problems in some electrical systems such as transformer coils.