GE D90 Plus Instruction Manual page 369

CHAPTER 7: PROTECTION
PLUS
D90 LINE DISTANCE PROTECTION SYSTEM – INSTRUCTION MANUAL
Voltage Pickup
Range: 0.000 to 1.500 pu in steps of 0.001
Default: 0.850 pu
This setting specifies a pickup level for the phase voltages from both sides of the breaker.
If six VTs are available, opening the breaker leads to two possible combinations – live
voltages from only one side of the breaker, or live voltages from both sides of the
breaker. Either case will set the scheme ready for flashover detection upon detection of
voltage above the selected value. Set this value to 85 to 90% of the nominal voltage.
Voltage Difference Pickup
Range: 0 to 100000 volts in steps of 1
Default: 1000 volts
This setting specifies a pickup level for the phase voltage difference when two VTs per
phase are available across the breaker. The pickup voltage difference should be below
the monitored voltage difference when close or open breaker resistors are left in service.
The setting is selected as primary volts difference between the sources.
Current Pickup
Range: 0.000 to 1.500 pu in steps of 0.001
Default: 0.600 pu
This setting specifies the normal load current which can flow through the breaker.
Depending on the flashover protection application, the flashover current can vary from
levels of the charging current when the line is de-energized (all line breakers open), to
well above the maximum line (feeder) load (line/feeder connected to load).
Pickup Delay
Range: 0.000 to 65.535 seconds in steps of 0.001
Default: 0.100 seconds
This setting specifies the time delay to operate the breaker flashover element after a
pickup condition is detected.
Supervision A, Supervision B, Supervision C
Range: any FlexLogic™ operand or shared operand
Default: OFF
These settings specify operands (per breaker pole) that supervise the operation of the
element per phase. Supervision can be provided by operation of other protection
elements, breaker failure, and close and trip commands. A six-cycle time delay applies
after the selected operand resets.
Block
Range: any FlexLogic™ operand or shared operand
Default: OFF
Assertion of the operand assigned to this setting blocks operation of the breaker
flashover element.
Events
Range: Enabled, Disabled
Plus
Default: varies with UR
This setting enables and disables the logging of breaker flashover events in the
sequence of events recorder.
The logic for the breaker flashover element is shown below.
-series model; refer to the EnerVista UR
CONTROL ELEMENTS
Plus
Setup software
359