GE C70 Instruction Manual page 364

5.7 CONTROL ELEMENTS
• BREAKER RESTRIKE 1 HF DETECT: This setting enables/disables high-frequency (HF) pattern detection when
breaker restrike occurs. High-frequency pattern is typical for capacitor bank, cables, and long transmission line appli-
cations.
• BRK RSTR 1 BRK OPEN: This setting assigns a FlexLogic operand indicating the open position of the breaker. It must
be logic "1" when breaker is open. It is important to assign either 52 contact with this setting or breaker close command
with
BRK RSTR 1 CLS CMD
• BRK RSTR 1 OPEN CMD: This setting assigns a FlexLogic operand indicating a breaker open command. It must be
logic "1" when breaker is opened, either manually or from protection logic.
• BRK RSTR 1 CLS CMD: This setting assigns a FlexLogic operand indicating a breaker close command. It must be
logic "1" when breaker is closed.
5
d) VT FUSE FAILURE

PATH: SETTINGS CONTROL ELEMENTS
 VT FUSE FAILURE 1

Every signal source includes a fuse failure scheme.
The VT fuse failure detector can be used to raise an alarm and/or block elements that may operate incorrectly for a full or
partial loss of AC potential caused by one or more blown fuses. Some elements that might be blocked (via the
are distance, voltage restrained overcurrent, and directional current.
There are two classes of fuse failure that occur:
• Class A: loss of one or two phases.
• Class B: loss of all three phases.
Different means of detection are required for each class. An indication of class A failures is a significant level of negative-
sequence voltage, whereas an indication of class B failures is when positive sequence current is present and there is an
insignificant amount of positive sequence voltage. Also rapid decrease in the phase voltages magnitude from a healthy
5-240
setting to give clear indication to the relay about breaker status.
Figure 5–110: BREAKER RESTRIKE SCHEME LOGIC

MONITORING ELEMENTS
VT FUSE FAILURE 1
FUNCTION: Disabled
 NEUTRAL WIRE OPEN 1
MESSAGE
 DETECTION: Disabled
 NEUTRAL WIRE OPEN 1
MESSAGE
 3 HARM PKP: 0.100
C70 Capacitor Bank Protection and Control System

VT FUSE FAILURE 1(6)
Range: Disabled, Enabled
Range: Disabled, Enabled
Range: 0.000 to 3.000 pu in steps of 0.001
5 SETTINGS
input)
BLOCK
GE Multilin