IG-267-EN versión 01; 07/04/2017
38
Protection functions General Instructions
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The settings for the second harmonic blocking unit are:
• Enabling the unit: Enable/disable the unit (ON/OFF).
• Second harmonic threshold: Second harmonic current
threshold (as a percentage relative to the fundamental
current) as of which the second harmonic condition is
met (from 5.0 % to 100.0 %).
• Cross-blocking: Setting to select how blocking a phase
(A, B or C) affects the other phases (also known as cross-
blocking). Possible settings:
- OFF: Indicates that there is no cross-blocking. In
other words, the second harmonic blocking signal
is only activated in those phases which meet the
conditions.
- 1 OUT OF 3: Indicates that there is cross-blocking.
In other words, blocking conditions simply need to
exist in any of the three phases in order to activate
the second harmonic blocking signal in all phases
(A, B and C).
- 2 OUT OF 3: As in the previous case, although this
time the blocking conditions must be found in at
least 2 of the 3 phases in order to activate the second
harmonic blocking signal in all phases (A, B and C).
• Minimum current threshold for phases: Fundamental
phase current as of which the condition corresponding
to minimum fundamental current is met. Variable ranges
in accordance with the current transformers used.
• Minimum current threshold for neutral: Fundamental
neutral current as of which the condition corresponding
to minimum fundamental current is met. Variable ranges
in accordance with the current transformers used.
• Minimum current threshold for sensitive neutral:
Fundamental sensitive neutral current as of which the
condition corresponding to minimum fundamental
current is met. Variable ranges in accordance with the
current transformers used.
• Maximum current threshold for phases: Fundamental
phase current below which the condition corresponding
to maximum fundamental phase current is met. Variable
ranges in accordance with the current transformers
used.
• Maximum block time: Maximum time blocking will
remain active (from 0.01 s to 5.00 s). If the block persists
after this time, the unit will be reset, releasing the
overcurrent units.
• Overcurrent units blocking mode: Mode in which the
corresponding overcurrent unit can be blocked (OFF,
UNIT, TIMING or TRIP).
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