GE L90 Instruction Manual page 393

CHAPTER 5: SETTINGS
The phase mho distance function uses a dynamic 100% memory-polarized mho characteristic with additional reactance,
directional, and overcurrent supervising characteristics. When set to "Non-directional," the mho function becomes an
offset mho with the reverse reach controlled independently from the forward reach, and all the directional characteristics
removed.
The phase quadrilateral distance function has a reactance characteristic, right and left blinders, and 100% memory-
polarized directional and current supervising characteristics. When set to "Non-directional," the quadrilateral function
applies a reactance line in the reverse direction instead of the directional comparators.
Each phase distance zone is configured individually through its own setting menu. All of the settings can be independently
modified for each of the zones except:
• The setting (common for the distance elements of all zones as entered under
SIGNAL SOURCE
ELEMENTS  SETTING GROUP 1(6)  DISTANCE
• The setting (common for the distance elements of all zones as entered under
MEMORY DURATION
GROUPED ELEMENTS  SETTING GROUP 1(6)  DISTANCE
The common distance settings described earlier must be chosen properly for correct operation of the phase distance
elements.
Although all zones can be used as either instantaneous elements (pickup [
time-delayed elements (operate [
tripping mode.
Ensure that the Phase VT Secondary Voltage setting (see the
 VOLTAGE BANK
action.
— All phase distance zones are reversible. The forward direction is defined by the
PHS DIST Z1 DIR
whereas the reverse direction is shifted 180° from that angle. The non-directional zone spans between the forward reach
impedance defined by the
PHS DIST Z1 REACH
and
PHS DIST Z1 REV REACH PHS DIST Z1 REV REACH RCA
— This setting selects the shape of the phase distance function between the mho and quadrilateral
PHS DIST Z1 SHAPE
characteristics. The selection is available on a per-zone basis. The two characteristics and their possible variations are
shown in the following figures.
L90 LINE CURRENT DIFFERENTIAL SYSTEM – INSTRUCTION MANUAL
PHS DIST Z1 QUAD

RGT BLD RCA: 85°
PHS DIST Z1 QUAD

LFT BLD: 10.00 Ω
PHS DIST Z1 QUAD

LFT BLD RCA: 85°
PHS DIST Z1

SUPV: 0.200 pu
PHS DIST Z1 VOLT

LEVEL: 0.000 pu
PHS DIST Z1

DELAY: 0.000 s
PHS DIST Z1 BLK:

Off
PHS DIST Z1

TARGET: Self-reset
PHS DIST Z1

EVENTS: Disabled
)
)
] FlexLogic operands), only zone 1 is intended for the instantaneous under-reaching
OP
menu) is set correctly to prevent improper operation of associated memory
and
PHS DIST Z1 RCA
as illustrated in the following figures.
Range: 60 to 90° in steps of 1
Range: 0.02 to 500.00 ohms in steps of 0.01
Range: 60 to 90° in steps of 1
Range: 0.050 to 30.000 pu in steps of 0.001
Range: 0.000 to 5.000 pu in steps of 0.001
Range: 0.000 to 65.535 s in steps of 0.001
Range: FlexLogic operand
Range: Self-reset, Latched, Disabled
Range: Disabled, Enabled
] and dropout [
PKP DPO
SETTINGS  SYSTEM SETUP  AC INPUTS
settings, and the reverse reach impedance defined by
GROUPED ELEMENTS
SETTINGS  GROUPED
SETTINGS 
] FlexLogic operands) or
setting,
PHS DIST Z1 RCA
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