Manual MRI3 GB
Woodward
DOK-TD-MRI3 Rev.A
31
5.3 System
parameter
5.3.1 Display of measuring values as primary quantities (I
prim
phase)
With this parameter it is possible to show the indication as primary measuring value. For this pur-
pose the parameter must be set to be equal with the rated primary CT current. If the parameter is
set to "SEK", the measuring value is shown as a multiple of the rated secondary CT current.
Example:
The current transformer used is of 1500/5 A. The flowing current is 1380 A. The parameter is set to
1500 A and on the display "1380 A" are shown. If the parameter is set to "SEK", the value shown
on the display is "0.92" x In.
Note:
The pick-up value is set to a multiple of the rated secondary CT current.
5.3.2 Display of earth current as primary quantity (I
prim
earth)
The parameter of this function is to be set in the same way as that described under 5.3.1. If the pa-
rameter is not set to "SEK", to relay types MRI3-X and MRI3-XR it applies too, that the measuring
value is shown as primary current in ampere. Apart from that the indication refers to % of I
N
.
5.3.3 Display of residual voltage U
E
as primary quantity (U
prim
/U
sec
)
The residual voltage can be shown as primary measuring value. For this parameter the transforma-
tion ratio of the VT has to be set accordingly. If the parameter is set to "SEK", the measuring value
is shown as rated secondary voltage.
Example:
The voltage transformer used is of 10 kV/100 V. The transformation ratio is 100 and this value has
to be set accordingly. If still the rated secondary voltage should be shown, the parameter is to be
set to 1.
5.3.4 Voltage transformer connection for residual voltage measuring
(3pha/e-n/1:1)
Depending on the connection of the voltage transformer of ER/XR-relay types three possibilities of
the residual voltage measurement can be chosen (see chapter 4.5).
5.3.5 Nominal
frequency
The adapted FFT-algorithm requires the nominal frequency as a parameter for correct digital sam-
pling and filtering of the input currents.
By pressing <SELECT> the display shows "f=50" or "f=60". The desired nominal frequency can be
adjusted by <+> or <-> and then stored with <ENTER>.