GE L90 Instruction Manual page 489

CHAPTER 5: SETTINGS
The TARGET setting is not user-selectable and forced to "Disabled". If Targets are required from directional
elements, it can be achieved by assigning directional element output to a digital element, where targets selection
can be used as required.
The phase directional elements (one for each of phases A, B, and C) determine the phase current flow direction for steady
state and fault conditions and can be used to control the operation of the phase overcurrent elements via the
of these elements.
This element is intended to apply a block signal to an overcurrent element to prevent an operation when current is flowing
in a particular direction. The direction of current flow is determined by measuring the phase angle between the current
from the phase CTs and the line-line voltage from the VTs, based on the 90° or quadrature connection. If there is a
requirement to supervise overcurrent elements for flows in opposite directions, such as can happen through a bus-tie
breaker, two phase directional elements should be programmed with opposite element characteristic angle (ECA) settings.
L90 LINE CURRENT DIFFERENTIAL SYSTEM – INSTRUCTION MANUAL
PHASE DIR 1

ECA: 30°
PHASE DIR POL V1

THRESHOLD: 0.700 pu
PHASE DIR 1 BLOCK

WHEN V MEM EXP: No
PHASE DIR 1

TARGET: Self-reset
PHASE DIR 1

EVENTS: Disabled
Figure 5-144: Phase A directional polarization
GROUPED ELEMENTS
Range: 0 to 359° in steps of 1
Range: 0.004 to 3.000 pu in steps of 0.001
Range: No, Yes
Range: Self-reset, Latched, Disabled
Range: Disabled, Enabled
inputs
BLOCK
5
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