CHAPTER 7: PROTECTION
GROUPED PROTECTION ELEMENTS
D90
PLUS
LINE DISTANCE PROTECTION SYSTEM – INSTRUCTION MANUAL
249
Forward ECA
Range: –90 to 90° in steps of 1
Default: –70°
This setting defines the characteristic angle (ECA) for the forward direction in the voltage
polarizing mode. The current polarizing mode uses a fixed ECA of 0°. The ECA 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 defines a symmetrical (in both directions from the ECA) limit angle for the
forward direction.
Forward Pickup
Range: 0.006 to 30.000 pu in steps of 0.001
Default: 0.050 pu
This setting defines the pickup level for the overcurrent unit of the element in the
forward direction. When selecting this setting it must be kept in mind that the design
uses a positive-sequence restraint technique for the “Calculated 3I0” mode of operation.
Reverse Limit Angle
Range: 40 to 90° in steps of 1
Default: 90°
This setting defines a symmetrical (in both directions from the ECA) limit angle for the
reverse direction.
Reverse Pickup
Range: 0.006 to 30.000 pu in steps of 0.001
Default: 0.050 pu
This setting defines the pickup level for the overcurrent unit of the element in the reverse
direction. When selecting this setting it must be kept in mind that the design uses a
positive-sequence restraint technique for the “Calculated 3I0” mode of operation.
Block
Range: any FlexLogic™ operand or shared operand
Default: Off
Assertion of the operand assigned to this setting blocks operation of the neutral
directional overcurrent element.
Events
Range: Enabled, Disabled
Default: varies with UR
Plus
-series model; refer to the EnerVista UR
Plus
Setup software
This setting enables and disables the logging of neutral directional overcurrent events in
the sequence of events recorder.
The logic for the neutral directional overcurrent 1 element is shown below. The logic is
identical for both neutral directional overcurrent elements.