GE Multilin G650, Manual

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5-88 G650 Generator Protection & Control System GEK-113285A
5.5 CONTROL ELEMENTS 5 SETTINGS
5
5.5.5 BREAKER FAILURE ELEMENT (50BF) (ENHANCED MODELS ONLY)
Note
: The Switchgear element used in the
Breaker Failure
element is the one configured in the
Number of Switchgear
setting, inside
Breaker settings
at
Setpoint > Protection Elements > Breaker > Breaker settings
The breaker failure element is used to determine when a trip command sent to a breaker has not been executed within a
selectable delay. Most commonly it is a failure to open from the tripped breaker. In the event of a breaker failure, the 50BF
element must issue a signal that will trip the rest of breakers connected at that time to the same busbar, and that can
provide fault current.
Comparing the current measured by the Relay with a setting level makes breaker failure detection. If after receiving a
breaker initiate signal, the current level is maintained over the set level for a time period longer than the set time, this
indicates that the breaker that has received the opening command has not been able to open and clear the fault. The relay
would issue the corresponding breaker failure signal.
G650 elements incorporate 2 levels of current and time, together with a trip without current element, and an internal arc
detection element.
The breaker failure Initiate signal is configured at
Setpoint > Relay Configuration > Protection Elements
. In the BRK
FAILURE INITIATE input, the user must select the desired signal for the breaker failure initiation.
The following table describes the breaker failure element settings:
Setpoint > Control Elements > Breaker Failure
Table 5–84: 50BF ELEMENT SETTINGS
Settings description for breaker failure element:
Function permission (Function):
This setting allows enabling and disabling the 50BF element
Supervision or retrip pickup level (Supervision Pickup):
Supervision level pickup current threshold
Hiset pickup level (Hiset Pickup):
High-level pickup current threshold.
Lowset pickup level (Loset Pickup):
Low level pickup current threshold.
Internal arc pickup level (Internal Arc Pickup):
Internal arc element pickup current threshold.
Internal arc time delay (Internal Arc Delay):
Time delay applied to the internal arc element
Supervision or Retrip time delay (Supervision Delay):
Time delay applied to the supervision or retrip element.
High-level time delay (Hiset Delay):
Time delay applied to the high level element.
Low-level time delay (Lowset Delay):
Time delay applied to the low level element.
2nd step time delay (2
nd
Step Delay):
Time delay applied to the breaker failure second step.
No current element time delay (No Current Delay):
Time delay applied to the trip without current element.
SETPOINT > CONTROL ELEMENTS > BREAKER FAILURE
SETTING DESCRIPTION NAME DEFAULT VALUE STEP RANGE
Function permission Function DISABLED N/A [DISABLED – ENABLED]
Supervision (retrip) pickup level Supervision Pickup 1.00 0.01 A [0.05 : 160.00]
Hiset pickup level Hiset Pickup 5.00 0.01 A [0.05 : 160.00]
Lowset pickup level Lowset Pickup 2.00 0.01 A [0.05 : 160.00]
Internal arc pickup level Internal Arc Pickup 0.10 0.01 A [0.05 : 160.00]
Internal arc time delay Internal Arc Delay 10.00 0.01 s [0.00 : 900.00]
Retrip time delay Supervision Delay 10.00 0.01 s [0.00 : 900.00]
Hiset time delay HiSet Delay 10.00 0.01 s [0.00 : 900.00]
Lowset time delay LowSet Delay 10.00 0.01 s [0.00 : 900.00]
Second stage time delay 2nd Step Delay 10.00 0.01 s [0.00 : 900.00]
WITHOUT current element time delay No Current Delay 10.00 0.01 s [0.00 : 900.00]
Snapshot event generation Snapshot Events ENABLED N/A [DISABLED – ENABLED]