Test online e offline

Testing power or distribution in the field is a demanding task for service engineers or commissioning teams today. Such tests can be done online, means the transformer is energized and connected to the grid or offline, means it is powered by a mobile power system. Both methods do have advantages and disadvantages as listed below:

Online testing:

+ Transformer is under load condition (full current)

+ Rated voltage and frequency

- No variable voltage and frequency

- Mostly no access to the transformer tank

- difficult for fault investigations

- PDIV and PDEV cannot be distinguished

Offline testing:

+ Full variable voltage and switchable frequencies