Table 452: 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.
4.1.7.5
Operation principle
The function can be enabled and disabled with the
Operation setting. The
corresponding parameter values are "On" and "Off".
The operation of JAMPTOC can be described with a module diagram. All the
modules in the diagram are explained in the next sections.
Level
detector 1
OPERATE
START
BLOCK
I_A
I_B
I_C
I3P
t
Timer
Blocking
logic
Figure 232: Functional module diagram
Level detector
The measured phase currents are compared to the set
Start value. The TRMS values
of the phase currents are considered for the level detection. The timer module is
enabled if at least two of the measured phase currents exceed the set
Start value.
Timer
Once activated, the internal
START
signal is activated. The value is available only
through the Monitored data view. The time characteristic is according to DT. When
the operation timer has reached the
Operate delay time value, the
OPERATE
output
is activated.
When the timer has elapsed but the motor stall condition still exists, the
OPERATE
output remains active until the phase currents values drop below the
Start value,
that is, until the stall condition persists. If the drop-off situation occurs while the
operating time is still counting, the reset timer is activated. If the drop-off time
exceeds the set
Reset delay time, the operating timer is reset.
1MRS759142 F
Protection functions
REX640
Technical Manual
399