Schemes Flashcards
1
Q
What is SEF?
A
Sensitive Earth Fault protection.
A relay measures differences between three phases; often an open-delta voltage check (0V).
2
Q
What is REF, and where is it used?
A
Restricted Earth Fault protection. Operates between CTs (unit protection). Used on transformers
3
Q
What is an O/C check?
A
Overcurrent check.
Used on CB fail schemes to check if CB has opened.
