Before enters Service:
- To verify the quality and condition of the gas in the equipment prior to the latter being put into service; typically SF6 percentage and humidity are measured,
- To determine if SF6 decomposition products are present, though normally the result should always be below the permitted levels for re-used.
During Equipment Service:
- Periodically(maintenance regime)
Typically SF6 percentage, decomposition products and humidity are measured. these tests can identify potential problems such as:
- Dielectric activities(PD, corona).
- Nozzle wear.
- Hot spots (high contact resistance).
- Non-standard switching conditions (heavy duty switching operations).
- Sealing problems (humidity, air).
- Improper gas handling (humidity, air, oil).
- After an event
Following a failure may be used as part of the investigation process:
- To identify the compartment following internal flash over.
- To identify the level of decomposition products
- To investigate an abnormal behavior highlighted by other factors, i.e. to identify if the problem is within a gas compartment.
- To correlate results obtained from other condition assessment techniques(PD measurements).