GE D90 Plus Instruction Manual page 274

GROUPED PROTECTION ELEMENTS
264
Pos Seq Restraint
Range: 0.000 to 0.500 in steps of 0.001
Default: 0.063
This setting controls the amount of the positive-sequence restraint. Set it to zero to
remove the restraint. Set it to a higher value if large system unbalances or poor CT
performance are expected.
Forward ECA
Range: 0 to 90° Lag in steps of 1
Default: 75° Lag
This setting specifies the element characteristic angle (ECA) for the forward direction.
The element characteristic angle in the reverse direction is the angle set for the forward
direction shifted by 180°.
Forward Limit Angle
Range: 40 to 90° in steps of 1
Default: 90°
This setting specifies a symmetrical limit angle (in both directions from the element
characteristic angle) for the forward direction.
Forward Pickup
Range: 0.015 to 30.000 pu in steps of 0.005
Default: 0.050 pu
This setting specifies the pickup level for the overcurrent unit in the forward direction.
This pickup threshold applies to zero-sequence or negative-sequence current based on
the setting. When specifying this setting, keep in mind that the design uses a
Type
positive-sequence restraint technique.
Reverse Limit Angle
Range: 40 to 90° in steps of 1
Default: 90°
This setting specifies a symmetrical limit angle (in both directions from the element
characteristic angle) for the reverse direction.
Reverse Pickup
Range: 0.015 to 30.000 pu in steps of 0.005
Default: 0.050 pu
This setting specifies the pickup level for the overcurrent unit in the reverse direction.
This pickup threshold applies to zero-sequence or negative-sequence current based on
the Type setting. When specifying this setting, keep in mind that the design uses a
positive-sequence restraint technique.
Block
Range: any FlexLogic operand or shared operand
Default: Off
Assertion of the operand assigned to this setting blocks operation of the negative-
sequence directional overcurrent element.
Events
Range: Enabled, Disabled
Plus
Default: varies with UR
This setting enables and disables the logging of negative-sequence directional
overcurrent events in the sequence of events recorder.
The figure shows the logic for the negative-sequence directional overcurrent 1 element.
The logic is identical for all negative-sequence directional overcurrent elements.
-series model; see the EnerVista UR
PLUS
D90 LINE DISTANCE PROTECTION SYSTEM – INSTRUCTION MANUAL
CHAPTER 7: PROTECTION
Plus
Setup software