MICROENER MM30-D - Overcurrent and Earth Fault Protection; Overcurrent Protection (F51); Earth Fault Protection (F64)

MM30-D
Doc. N° MO-0037-ING
Rev. 4
Date 24.02.2003
Copyright 2010 - Microener
Pag
10
of
36
2.2.3.6 - F51 - Overcurrent protection
- Minimum Pick-up Current level in at least one phase :
I> = (1-5)Ist, step 0.1 Ist (limited to 20 times In)
Ist (motor locked rotor current) = (0.5-10)Im, step 0.1Im
lf I> = DIS. the function is disactivated
- Trip time delay
tI> = (0.05-1)s, step 0,01s.
Any of the output relays can be associated to the time delayed element “tI>” as well as to the
instantaneous element “I>” of this function for signalling or for blocking other relays. The
output relay controlled by the I> level remains energized for the time tI> + tBO.
After this delay the relay it is anyhow reset.
tBO = (0.05-0.5)s, step 0.05s.
2.2.3.7 - F64 - Earth Fault protection
- Minimum Pick-up Zero Sequence Residual Current level :
O> = (0.02 - 2)On, step 0.01On. lf O> = DIS. the function is disactivated.
- Trip time delay:
tO> = (0.05-5)s, step 0.01s.
- Minimum Residual Voltage level to enable the operation of the Zero Sequence O/C element
when in the Directional mode:
Uo> = (2-25)secondary V, step 1V.
- Max torque angle in the Directional operation mode (see § 2.3):
 = (0-359-Dis)°, step 1°.
When “  “ is set to “Dis”, the Earth Fault element works as normal non directional
Overcurrent relay and the “ Uo “ level is disregarded.
As for function F51, any of the output relays can be associated to the instantaneous element
of “O>” as well as to the time delayed element “ tO> “.