GE P24DM - Stall During Running; Momentary Reduction in System Voltage During Running; Reacceleration after a Reduction in System Voltage; Figure 74: Reacceleration Detection

14.3 STALL DURING RUNNING
A stall during running is given by a current exceeding the programmed current threshold, (Stall Setting) following a
successf
ul start. The Successful Start signal is issued if the current decreases below the starting current and/or CB
still close (depending on start criteria) when Prol. Start Time is timed out). If the current fails to fall below the
current threshold before the stall time delay has elapsed, a trip is initiated (Stall Rotor-run).
14.4 MOMENTARY REDUCTION IN SYSTEM VOLTAGE DURING RUNNING
To find Reacceleration, Low voltage Ride Through and Auto Restart protection functions, go to the relay menu Stall
Detection.
14.5 REACCELERATION AFTER A REDUCTION IN SYSTEM VOLTAGE
If there is a low voltage condition on the system for more than 100 ms, once the voltage has recovered, the current
exceeds the stalling curr
ent threshold within 5 seconds (Reac in Progress), the stall protection is disabled to allow
for reacceleration. A settable undervoltage threshold Reac. Low V Set makes it possible to detect a voltage drop.
V00789
Stall Setting
Prol. Start Time
Fixed 5s interval
Scenario 2
Due to trip in caseof
Scenario 2
Time
Time
Time
Current
Low V Detection
Start Successful
0
0
0
1
1
t
0
t
1
At the time t
1
when the timeris
timed out and scenario
2 is true
,
the re lay trips on “Stal l Prol.
Start”.
In case of scenario
1
there
is no trip.
Prol.
Start Time timer starts if current has
increased above “Stall Setting” threshold
within the 5 seconds interval. During this
period Stall function is disabled and
Reac In Progress is asserted
.
Scenario 1
Starting Current
Figure 74: Reacceleration detection
The figur
e above shows the setting thresholds. If the current fails to fall below the stalling current threshold before
the end of the Prol.Start Time (Scenario 2), the relay generates a tripping order (Reacc Low Volt.).
If the current exceeds the stall setting threshold after the 5 s window used for reacceleration criteria, the stall
protection is enabled and a trip occurs. The Stall Rotor Run trips if the current stays above the stall setting
threshold when the Stall Time timer has timed out.
This function is disabled during the starting period. This period begins when Strt in progress is asserted and ends
when Strt successful is asserted.
Chapter 6 - Current Protection Functions P24xM
150 P24xM-TM-EN-2.1