GE Power Management
LPS-D Line Protection System
2-
19
2 CALCULATION OF SETTINGS
2.3 PROTECTION SETTINGS
2
operate on current alone and thus provide a continuous output for a zero voltage fault right at the relay loca-
tion. A continuous output is required from the Zone 4 functions in some schemes to insure that incorrect trip-
ping does not occur for certain fault conditions.
Figure 2–7: R-X DIAGRAM FOR ZONE 4 DISTANCE FUNCTIONS
For example, consider the fault at F1 in Figure 2–8: ZONE 4 FAULT EXAMPLE and assume that a blocking
scheme is being used in the protected line. A continuous blocking signal must be sent to the remote terminal to
block tripping there until the fault is cleared. Offset in the Zone 4 functions will assure this condition. Offset will
also assure that Zone 4 time-delayed backup (when used) will also be provided for zero voltage faults.
Figure 2–8: ZONE 4 FAULT EXAMPLE
The Zone 4 phase distance functions in the LPS-D are not provided with offset because they use an adaptive
memory feature to provide the operation needed for bolted three-phase faults at the relay location. The adap-
tive memory works as follows:
1.
If the fault voltage is less than 10 percent of rated voltage then the voltage prior to the fault will be used to
polarize the Zone 4 functions. This voltage will be held, and the functions will remain picked up, until the
fault is cleared, at which time they will reset.
2.
If the voltage is greater than 10 percent of rated voltage, then the voltage prior to the fault will be held for 5
cycles and will then revert to the actual fault voltage. The functions will stay picked up for the duration of
the fault and will reset when the fault clears.
In either case, the functions will provide a continuous output for the duration of the fault and will thus meet the
requirements of the particular application.
401: Z4PHASE - Zone 4 Phase Distance
Z4PHASE can be set to YES or NO and determines whether or not the functions are to be used in the applica-
tion.
•
Blocking, Hybrid and POTT2 Schemes
The Zone 4 phase distance functions are always required in these schemes, therefore, set:
Z4PHASE = YES
Zr
X
R
OFFSET
B
A
Z2A
Z4B
PROTECTED LINE
F1
Содержание LPS-D
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Страница 164: ...3 14 LPS D Line Protection System GE Power Management 3 3 PRINTED CIRCUIT BOARD MODULES 3 HARDWARE DESCRIPTION 3 ...
Страница 226: ...7 4 LPS D Line Protection System GE Power Management 7 1 RATINGS 7 SPECIFICATIONS 7 ...
Страница 284: ...10 20 LPS D Line Protection System GE Power Management 10 8 HELP MENU 10 ALPS TEST PROGRAM 10 ...
Страница 334: ...A 4 LPS D Line Protection System GE Power Management A 1 FREQUENTLY ASKED QUESTIONS APPENDIXA A ...
Страница 412: ...C 34 LPS D Line Protection System GE Power Management C 3 POINT LISTS APPENDIXC C ...
Страница 416: ...D 4 LPS D Line Protection System GE Power Management D 1 KEYPAD MENUS APPENDIXD D ...
Страница 422: ...F 2 LPS D Line Protection System GE Power Management F 1 WARRANTY INFORMATION APPENDIXF F ...
Страница 435: ...GE Power Management LPS D Line Protection System xiii INDEX INDEX tests 6 11 ZONE TIMER functional tests 5 10 ...
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