GE D60 Instruction Manual page 276

5.6 CONTROL ELEMENTS
The detection of the breaker flashover is based on the following condition:
1. Breaker open,
2. Voltage drop measured from either side of the breaker during the flashover period,
3. Voltage difference drop, and
4. Measured flashover current through the breaker.
Furthermore, the scheme is applicable for cases where either one or two sets of three-phase voltages are available across
the breaker.
THREE VT BREAKER FLASHOVER APPLICATION
When only one set of VTs is available across the breaker, the
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an open breaker condition in this application, the scheme checks if the per-phase voltages were recovered (picked up), the
status of the breaker is open (contact input indicating the breaker status is off), and no flashover current is flowing. A con-
tact showing the breaker status must be provided to the relay. The voltage difference will not be considered as a condition
for open breaker in this part of the logic.
Voltages must be present prior to flashover conditions. If the three VTs are placed after the breaker on the
line (or feeder), and the downstream breaker is open, the measured voltage would be zero and the flash-
over element will not be initiated.
NOTE
The flashover detection will reset if the current drops back to zero, the breaker closes, or the selected FlexLogic™ operand
for supervision changes to high. Using supervision through the
trip operand that will not allow the flashover element to pickup prior to the trip.
The flashover detection can be used for external alarm, re-tripping the breaker, or energizing the lockout relay.
Consider the following configuration:
The source 1 (SRC1) phase currents are feeder CTs and phase voltages are bus VTs, and Contact Input 1 is set as Breaker
52a contact. The conditions prior to flashover detection are:
1. 52a status = 0
2. VAg, VBg, or VCg is greater than the pickup setting
3. IA, IB, IC = 0; no current flows through the breaker
4. ΔVA is greater than pickup (not applicable in this scheme)
5-186
BKR 1 FLSHOVR SPV B:
MESSAGE
Off
BKR 1 FLSHOVR SPV C:
MESSAGE
Off
BKR 1 FLSHOVR BLOCK:
MESSAGE
Off
BKR 1 FLSHOVR TAR-
MESSAGE
GET: Self-reset
BKR 1 FLSHOVR
MESSAGE
EVENTS: Disabled
Bus
CTs
Bus VTs
D60 Line Distance Relay
Range: FlexLogic™ operand
Range: FlexLogic™ operand
Range: FlexLogic™ operand
Range: Self-reset, Latched, Disabled
Range: Disabled, Enabled
setting should be "None". To detect
BRK FLSHOVR SIDE 2 SRC
setting is recommended by selecting a
BRK FLSHOVR SPV
Breaker
Line/Feeder
842746A1.CDR
5 SETTINGS
GE Multilin