CHAPTER 5: SETTINGS
GROUPED ELEMENTS
L90 LINE CURRENT DIFFERENTIAL SYSTEM – INSTRUCTION MANUAL
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5
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
SIGNAL SOURCE
setting (common for the distance elements of all zones as entered under
SETTINGS
GROUPED
ELEMENTS
SETTING GROUP 1(6)
DISTANCE
)
•
The
MEMORY DURATION
setting (common for the distance elements of all zones as entered under
SETTINGS
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 [
PKP
] and dropout [
DPO
] FlexLogic operands) or
time-delayed elements (operate [
OP
] FlexLogic operands), only zone 1 is intended for the instantaneous under-reaching
tripping mode.
PHS DIST Z1 DIR
— All phase distance zones are reversible. The forward direction is defined by the
PHS DIST Z1 RCA
setting,
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 RCA
settings, and the reverse reach impedance defined by
PHS DIST Z1 REV REACH
and
PHS DIST Z1 REV REACH RCA
as illustrated in the following figures.
PHS DIST Z1 SHAPE
— This setting selects the shape of the phase distance function between the mho and quadrilateral
characteristics. The selection is available on a per-zone basis. The two characteristics and their possible variations are
shown in the following figures.
PHS DIST Z1 QUAD
RGT BLD RCA: 85°
Range: 60 to 90° in steps of 1
PHS DIST Z1 QUAD
LFT BLD: 10.00
Ω
Range: 0.02 to 500.00 ohms in steps of 0.01
PHS DIST Z1 QUAD
LFT BLD RCA: 85°
Range: 60 to 90° in steps of 1
PHS DIST Z1
SUPV: 0.200 pu
Range: 0.050 to 30.000 pu in steps of 0.001
PHS DIST Z1 VOLT
LEVEL: 0.000 pu
Range: 0.000 to 5.000 pu in steps of 0.001
PHS DIST Z1
DELAY: 0.000 s
Range: 0.000 to 65.535 s in steps of 0.001
PHS DIST Z1 BLK:
Off
Range: FlexLogic operand
PHS DIST Z1
TARGET: Self-reset
Range: Self-reset, Latched, Disabled
PHS DIST Z1
EVENTS: Disabled
Range: Disabled, Enabled
Ensure that the Phase VT Secondary Voltage setting (see the
SETTINGS
SYSTEM SETUP
AC INPUTS
VOLTAGE BANK
menu) is set correctly to prevent improper operation of associated memory
action.