The use of Gas Insulated Substations (GIS) has been increased in recent years due to its advantages over the traditional Air Insulated Substations (AIS) (smaller, less maintenance work required, etcetera). However, the life of GIS is affected by several factors such as: conductive particles, partial discharges and contamination (decomposition products, water, etcetera).

Conductive particles inside the enclosure are known to reduce the breakdown level of gas insulated systems. Partial discharges can develop from conductive particles, contamination, defects during the manufacturing process, etcetera.

Acoustic Emission is capable of detecting both: conductive particles (metallic particles bouncing inside the enclosure) and partial discharges.