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2.3 PROTECTION SETTINGS
1403: ZLINE - Positive Sequence Line Impedance
ZLINE is used in determining fault location. Set ZLINE equal to the positive-sequence impedance of the pro-
tected line.
1404: ZEROSEQK0 - Zero Sequence Current Compensation
ZEROSEQK0 establishes the amount of zero-sequence current that is used in all of the ground-distance func-
2
tions (except Zone 1) to provide "self-compensation." This permits the reach setting for the ground-distance
functions to be based on the positive-sequence impedance of the protected line. Use the following setting:
ZEROSEQK0 =
Z
where:
= zero-sequence impedance of line
0 L
Z
= positive-sequence impedance of line
1 L
1405: LINELENGTH - Line Length
LINELENGTH is used as part the fault location algorithm and allows the LPS-D to report the location of the
fault in miles or kilometers (see Protection Setting 1406 below) relative to the relay location. Set LINELENGTH
equal to the length of the line in terms of the units used in Protection Setting 1406.
1406: LINEUNIT - Unit Of Length
The LPS-D will report the distance to the fault relative to the relay location. Set LINEUNIT equal to MILES if
location in miles is required, otherwise set LINEUNIT equal to KM.
1407: CTRATIO - Current Transformer Ratio
The LPS-D will report present values in terms of secondary values or primary values as determined by General
Setting 108: DISPLAYVAL. The ratio of the of the current transformers used to supply the system is used in
this procedure. Set CTRATIO equal to the CT ratio used with the LPS-D.
1408: PTRATIO - Potential Transformer Ratio
The LPS-D will report present values in terms of secondary values or primary values as determined by General
Setting 108: DISPLAYVAL. The ratio of the of the potential transformers used to supply the system is used in
this procedure. Set PTRATIO equal to the PT ratio used with the LPS-D.
An internal DTA (digital to analog) function, standard on the LPS-D, provides the following:
1. An analog output proportional to the distance from the relay to the fault as calculated by the fault-location
algorithm.
2. Four contact outputs that provide fault-type information (configurable).
The analog output is intended to be wired into an analog port of a SCADA RTU to provide remote indication of
distance to the fault. The four contact output assignments are designated phase A (Index 60), phase B (Index
61), phase C (Index 62), and neutral (Index 63) and are intended to be wired into four separate RTU ports. A
particular contact closes when its phase (or neutral) is involved in the fault. For a phase B-to-C-to-ground fault,
the phase B, phase C, and neutral contacts close. The contact assignments can be made from the keypad, or
by using Xpression Builder.
The DTA provides either a nominal 0 to 1 mA DC output or a nominal 0 to 5 V DC output. The choice of output
ranges is made by a switch located on the Processor Board.
2-
40
⁄
Z
Z
0 L
1 L
LPS-D Line Protection System
2 CALCULATION OF SETTINGS
2.3.16 SCADA DTA
GE Power Management
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