GE D60 Instruction Manual page 277

5 SETTINGS
The conditions at flashover detection are:
1. 52a status = 0
2. VAg, VBg, or VCg is lower than the pickup setting
3. IA, IB, or IC is greater than the pickup current flowing through the breaker
4. ΔVA is greater than pickup (not applicable in this scheme)
SIX VT BREAKER FLASHOVER APPLICATION
The per-phase voltage difference approaches zero when the breaker is closed. The is well below any typical minimum
pickup voltage. Select the level of the
across the breaker when the close or open breaker resistors are left in service. Prior to flashover, the voltage difference is
larger than
BRK 1(2) FLSHOVR DIFF V PKP
voltage from one side of the breaker has dropped to zero – line de-energized), at least one per-phase voltage is larger than
the
BRK 1(2) FLSHOVR V PKP
phase voltages from both sides of the breaker drops below the pickup value defined by the
the voltage difference drops below the pickup setting, and flashover current is detected. These flashover conditions initiate
FlexLogic™ pickup operands and start the
This application do not require detection of breaker status via a 52a contact, as it uses a voltage difference larger than the
setting. However, monitoring the breaker contact will ensure scheme stability.
BRK 1(2) FLSHOVR DIFF V PKP
Consider the following configuration:
The source 1 (SRC1) phase currents are CTs and phase voltages are bus VTs. The source 2 (SRC2) phase voltages are
line VTs. Contact Input 1 is set as Breaker 52a contact (optional).
The conditions prior to flashover detection are:
ΔVA is greater than pickup
1.
2. VAg, VBg, or VCg is greater than the pickup setting
3. IA, IB, IC = 0; no current flows through the breaker
4. 52a status = 0 (optional)
The conditions at flashover detection are:
ΔVA is less than pickup
1.
2. VAg, VBg, or VCg is lower than the pickup setting
3. IA, IB, or IC is greater than the pickup current flowing through the breaker
4. 52a status = 0 (optional)
The element is operational only when phase-to-ground voltages are connected to relay terminals. The
flashover element will not operate if delta voltages are applied.
NOTE
The Breaker Flashover settings are described below.
• BRK FLSHOVR SIDE 1 SRC: This setting specifies a signal source used to provide three-phase voltages and three-
phase currents from one side of the current breaker. The source selected as a setting and must be configured with
breaker phase voltages and currents, even if only 3 VTs are available across the breaker.
GE Multilin
BRK 1(2) FLSHOVR DIFF V PKP
(applies to either the difference between two live voltages per phase or when the
setting, and no current flows through the breaker poles. During breaker flashover, the per-
BRK 1(2) FLSHOVR PKP DELAY
Bus
CTs Breaker
VTs
D60 Line Distance Relay
5.6 CONTROL ELEMENTS
setting to be less than the voltage difference measured
BRK 1(2) FLSHOVR V PKP
timer.
Line/Feeder
VTs
842745A1.CDR
setting,
5
5-187