functional overload & earth fault test ???

[emadshaaban]

hi electrical experts
we are tending to preform protection functional test for our feeders in power center
plz help in the following questions:
1) what is the stander for frequency of applying protection (each 1y,2y or 3y)?
2) what is the minimum difference of overload unit trip time between curve and actual?
3) can you give a jop plan for testing overload and earth fault?

 

[DTR2011]

1) See NETA Frequency of Tests
2) Minimum difference = 0 maximum difference can by +/- 20%, always check with manufacturers specifications.
3) What are you testing? Are these power circuit breakers with electronic trip units or medium voltage switchgear? - The NETA Maintenance Testing Specification defines these very well, for each type of equipment. Well worth the cost of the document. NETA MTS Spec