GE UR series, Instruction Manual

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GE Multilin L60 Line Phase Comparison System 5-231
5 SETTINGS 5.6 CONTROL ELEMENTS
5
d) CT FAILURE
PATH: SETTINGS
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CONTROL ELEMENTS
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MONITORING ELEMENTS
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CT FAILURE DETECTOR
The CT failure function is designed to detect problems with system current transformers used to supply current to the relay.
This logic detects the presence of a zero-sequence current at the supervised source of current without a simultaneous
zero-sequence current at another source, zero-sequence voltage, or some protection element condition.
The CT failure logic (see below) is based on the presence of the zero-sequence current in the supervised CT source and
the absence of one of three or all of the three following conditions.
1. Zero-sequence current at different source current (may be different set of CTs or different CT core of the same CT).
2. Zero-sequence voltage at the assigned source.
3. Appropriate protection element or remote signal.
The CT failure settings are described below.
• CT FAIL FUNCTION: This setting enables or disables operation of the CT failure element.
• CT FAIL BLOCK: This setting selects a FlexLogic™ operand to block operation of the element during some condition
(for example, an open pole in process of the single pole tripping-reclosing) when CT fail should be blocked. Local sig-
nals or remote signals representing operation of some remote current protection elements via communication chan-
nels can also be chosen.
• CT FAIL 3I0 INPUT 1: This setting selects the current source for input 1. The most critical protection element should
also be assigned to the same source.
• CT FAIL 3I0 INPUT 1 PICKUP: This setting selects the 3I_0 pickup value for input 1 (the main supervised CT source).
• CT FAIL 3I0 INPUT 2 : This setting selects the current source for input 2. Input 2 should use a different set of CTs or a
different CT core of the same CT. If 3I_0 does not exist at source 2, then a CT failure is declared.
• CT FAIL 3I0 INPUT 2 PICKUP : This setting selects the 3I_0 pickup value for input 2 (different CT input) of the relay.
• CT FAIL 3V0 INPUT: This setting selects the voltage source.
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CT FAILURE
„
DETECTOR
CT FAIL FUNCTION:
Disabled
Range: Disabled, Enabled
MESSAGE
CT FAIL BLOCK:
Off
Range: FlexLogic™ operand
MESSAGE
CT FAIL 3I0 INPUT 1:
SRC 1
Range: SRC 1, SRC 2
MESSAGE
CT FAIL 3I0 INPUT 1
PKP: 0.20 pu
Range: 0.00 to 2.00 pu in steps of 0.01
MESSAGE
CT FAIL 3I0 INPUT 2:
SRC 2
Range: SRC 1, SRC 2
MESSAGE
CT FAIL 3I0 INPUT 2
PKP: 0.20 pu
Range: 0.00 to 2.00 pu in steps of 0.01
MESSAGE
CT FAIL 3V0 INPUT:
SRC 1
Range: SRC 1, SRC 2
MESSAGE
CT FAIL 3V0 INPUT
PKP: 0.20 pu
Range: 0.00 to 2.00 pu in steps of 0.01
MESSAGE
CT FAIL PICKUP
DELAY: 1.000 s
Range: 0.000 to 65.535 s in steps of 0.001
MESSAGE
CT FAIL TARGET:
Self-reset
Range: Self-reset, Latched, Disabled
MESSAGE
CT FAIL EVENTS:
Disabled
Range: Disabled, Enabled