The Basis setting of REF protectionfor transformer should be how much.

Question

Accepted Answer

The Basis setting of REF protection for a transformer should be determined based on the transformer's characteristics and the system requirements.

The basis setting of REF (Restricted Earth Fault) protection for a transformer is typically determined by considering the transformer's winding configuration, impedance, and the system's fault level.
The setting should be chosen to ensure that the protection operates reliably for internal faults while avoiding unnecessary tripping for external faults.
The setting is usually expressed as a percentage of the transformer's winding impedance or the rated current.
For example, a common basis setting for REF protection is 10-20% of the transformer's winding impedance.
The specific setting may vary depending on factors such as the transformer's size, voltage level, and the system's fault current levels.

Accepted Answer

It should be 5 percent of differential protection basis setting.

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