GE D90 Plus Instruction Manual page 245

CHAPTER 7: PROTECTION
PLUS
D90 LINE DISTANCE PROTECTION SYSTEM – INSTRUCTION MANUAL
Source
Range: LINE (SRC 1), BKR 1 (SRC 2), BKR 2 (SRC 3)
Default: LINE (SRC 1)
This setting selects the signal source for the breaker failure protection element.
Current Supervision
Range: Yes, No
Default: Yes
If set to "Yes", the breaker failure element will only be initiated if current flowing through
the breaker is above the supervision pickup level.
Use Seal-In
Range: Yes, No
Default: Yes
If set to "Yes", the breaker failure element will only be sealed-in if current flowing through
the breaker is above the supervision pickup level.
Three Pole Initiate
Range: any FlexLogic™ operand or shared operand
Default: Off
This setting selects the operand that will initiate three-pole tripping of the breaker when
asserted.
Block
Range: any FlexLogic™ operand or shared operand
Default: Off
Assertion of the operand assigned to this setting blocks operation of the breaker failure
element.
Phase Current Supervision Pickup
Range: 0.001 to 30.000 pu in steps of 0.001
Default: 1.050 pu
This setting specifies the phase current initiation and seal-in supervision level. Generally,
this setting should detect the lowest expected fault current on the protected breaker. It
can be set as low as necessary (lower than breaker resistor current or lower than load
current). High-set and low-set current supervision will ensure correct operation.
Neutral Current Supervision Pickup
Range: 0.001 to 30.000 pu in steps of 0.001
Default: 1.050 pu
This setting specifies the neutral current initiate and seal-in supervision level. Generally,
this setting should detect the lowest expected fault current on the protected breaker.
Neutral current supervision is used only in the three phase scheme to provide increased
sensitivity. This setting is valid only for three-pole tripping schemes.
Use Timer 1
Range: Yes, No
Default: Yes
If this setting value is "Yes", the early path is operational.
Timer 1 Pickup Delay
Range: 0.000 to 65.535 seconds in steps of 0.001
Default: 0 seconds
Timer 1 is set to the shortest time required for breaker auxiliary contact Status-1 to
open, from the time the initial trip signal is applied to the breaker trip circuit, plus a
safety margin.
GROUPED PROTECTION ELEMENTS
237