Locked Rotor Unit Setpoints - GE Multilin F650 Instruction Manual

5 SETPOINTS
The Operation Threshold level has been included to allow the user selecting the current inhibition level suitable for a
particular application, in order to avoid operation of the unit when the relay is not connected to the line or in case the relay
has previously operated correctly and has been disconected from the line, as in this case the operation condition is met but
the relay should not trip.
The operation threshold operation is as follows:
The Broken conductor element will be fully operational if at least one of the phase current levels is higher than the setpoint.
This condition assumes that the relay is connected to the line.
If the unit is on trip or pickup condition, the element will be reset if the three phase currents are below the operation
threshold level. This condition assumes that the relay is not connected to the line and therefore the relay should not trip.
Due to the response time of this function, if the set time delay is 0s, a trip could occur in situations where, for example, one
of the currents is stopped before the rest, as these currents would produce a negative sequence current calculation.
Therefore, to avoid this kind of undesired trips, it is strongly recommended to establish a minimum time delay setpoint, such
as 100 ms, or higher depending on the expected normal unbalances in the network, to differentiate these situations from
broken conductor situations.
F650 units incorporate a locked rotor element with three units. Protection element 48 produces a trip when current
(primary values) exceeds the setpoint value. This current setpoint value is the product of the Full load current setpoint by
the pickup setpoint.
Setpoint > Control Elements > Locked Rotor
Table 5–82: LOCKED ROTOR UNIT SETPOINTS
SETPOINT > CONTROL ELEMENTS > LOCKED ROTOR
SETPOINT DESCRIPTION
Function permission
Input type
Full load current
Pickup level
Trip time
Reset time
Snapshot event generation
Locked rotor unit setpoints are:
Function Permission (Function):
Input (Phasor(DFT)-RMS):
Full Load Current (FLC):
Pickup Level:
Trip time (Trip Delay):
Reset time (Reset Delay):
GE Multilin
NAME DEFAULT VALUE STE
Function DISABLED
Input PHASOR(DFT)
Full Load Current 0.50
Pickup Level 1.01
Trip Delay 0.00
Reset Delay 0.00
Snapshot Events ENABLED
This setpoint indicates whether the locked rotor element is enabled or disabled.
Selection between fundamental phasor magnitude (DFT) or total waveform RMS
magnitude.
This is the average maximum expected operating phase current for the motor.
This is the current threshold over the full load current setpoint in which the unit will
operate. The operating current for this unit is calculated as follows:
=
I
tap
setpoint of the Protection element operation time.
Reset time of the Protection element.
F650 Digital Bay Controller
5.5 CONTROL ELEMENTS
RANGE
P
N/A [DISABLED – ENABLED]
N/A [PHASOR – RMS]
KA [0.10 : 10.00]
N/A [1.01 : 109.00]
s [0.00 : 900.00]
s [0.00 : 900.00]
N/A [DISABLED – ENABLED]
×
FLC PKP _ Level
5.5.9 LOCKED ROTOR
5
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