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 el
ement “
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 l
evel :
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>
“.
