GE L60 Instructions Manual page 417

Line phase comparison system
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CHAPTER 5: SETTINGS
A weak-infeed or no fault infeed at one end of the faulted line can prevent phase comparison element trip.
Consequently, instant conversion from weak-infeed logic with sending permissive continuous signal to fault logic with
sending square waves is required in case of the external fault at the adjacent or internal fault for proper operation of
phase comparison relay at the remote line's terminal.
Apply the open breaker echo element to any particular application according to local system conditions. The element
settings are as follows.
— Disables/enables the open breaker keying feature.
OPEN BREAKER KEYING
— Assigns a FlexLogic operand to control open/close state of breaker 1 with either 52a or 52b type
BRK 1 AUX CONTACT
contact to create logic "1" when the breaker is open.
— Selects a supervising element such as a test/normal switch usually used in breaker 1 control schemes
BRK 1 CONT SUPV
or any other elements. If no element is required, use the default value of "Off."
— If supervision of two breakers is required, this setting is used to assign a FlexLogic operand to control
BRK 2 AUX CONTACT
open/close state of the Breaker #2 with either 52a or 52b type contact to create logic "1" when the breaker is open.
— Selects a supervising element such as a test/normal switch usually used in breaker 2 control schemes
BRK 2 CONT SUPV
or any other elements. If no element is required, use the default value of "Off."
OPEN BREAKER KEYING PKP DELAY
and auxiliary contacts of the breaker or any other operating conditions.
OPEN BREAKER KEYING RST DELAY
auxiliary contacts of the breaker or any other operating conditions.
— Assigns a sensitive phase-current element for weak-infeed keying control. It should be normally
WEAK-INFEED KEYING
picked up with a minimum line load current. An instantaneous overcurrent element or a group of overcurrent elements are
suitable for this purpose.
— Selects a weak-infeed supervising element from FlexLogic operands. An undervoltage element,
WEAK-INFEED SUPV
auxiliary contacts of breakers indicating close position, or other elements can be useful for no-current supervision.
— Delays operation of weak-infeed keying during some transient conditions, such as breaker
WEAK-INFEED PICKUP DELAY
reclosure.
— The weak-infeed keying function incorporates a default 35 ms reset delay to assure reset
WEAK-INFEED RESET DELAY
coordination with the FDH trip-level fault detector at the remote terminal during fault clearing. The default reset time can
be changed according to local conditions.
L60 LINE PHASE COMPARISON SYSTEM – INSTRUCTION MANUAL
— Delays the operation of open breaker keying to override disagreement between main
— Delays the reset of open breaker keying to override disagreement between main and
GROUPED ELEMENTS
5
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