4.4.5.4
Analog channel configuration
MNSPTOC has one analog group input which must be properly configured.
Table 769: Analog inputs
Input
Description
I3P
Three-phase currents
See the preprocessing function blocks in this document for the possible
signal sources.
Improper analog channel configuration causes a validation error if the analog
channels are not completely configured or they do not match with certain settings.
For troubleshooting, check the contents of this chapter and also the preprocessing
blocks in this document. The configuration can be written to the protection relay
once the mismatch is corrected.
4.4.5.5
Operation principle
The function can be enabled and disabled with the
Operation setting. The
corresponding parameter values are "On" and "Off".
The operation of MNSPTOC can be described by using a module diagram. All the
modules in the diagram are explained in the next sections.
OPERATE
BLK_RESTART
START
BLOCK
I3P
I
2
Level
detector
t
Timer
t
ST_EMERG_ENA
Figure 477: Functional module diagram
Level detector
The calculated negative-sequence current is compared to the
Start value setting. If
the measured value exceeds the
Start value setting, the function activates the timer
module.
Timer
Once activated, the timer activates the
START
output. Depending on the value of
the set
Operating curve type, the time characteristics are according to DT or IDMT.
When the operation timer has reached the value set by
Operate delay time in the DT
mode or the maximum value defined by the inverse time curve, the
OPERATE
output
is activated.
Protection functions
1MRS759142 F
842
REX640
Technical Manual