Siemens SIPROTEC 4 7UT6 Series Manual page 22

Introduction
1.3 Characteristics
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High level of stability even with different degrees of current transformer saturation
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Monitoring of the current connections with operation currents
Busbar Protection
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Single-phase differential protection for a busbar with up to 7 or 9 or 12 feeders (depending on the
variant ordered)
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Either one relay per phase or one relay connected via interposed summation current transformers
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Tripping characteristic with current restraint
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Short tripping time
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Insensitivity to DC components and current transformer saturation
•
High level of stability even with different degrees of current transformer saturation
•
Monitoring of the current connections with operation currents.
Earth Fault Differential Protection
•
Earth fault protection for earthed transformer windings, generators, motors, shunt reactors, or starpoint
formers
•
Short command duration
•
High sensitivity for earth faults within the protected zone
•
High stability against external earth faults using the magnitude and phase relationship of through-
flowing earth current
•
2 restricted earth fault protection functions possible (only 7UT613/63x)
High-impedance Differential Protection
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Highly sensitive fault current detection using a common (external) burden resistor
•
Short tripping time
•
Insensitive against DC components and current transformer saturation
•
High stability with optimum matching
•
Suitable for earth fault detection on earthed generators, motors, shunt reactors, and transformers,
including auto-transformers, with or without earthed starpoint
•
Suitable for any voltage measurement (via the resistor current) for application of high-impedance unit
protection
Tank Leakage Protection
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For transformers or reactors the tank of which is installed isolated or with high resistance
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Monitoring of the current flowing between the tank and ground
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Can be connected via a „normal" current input of the device or the special highly sensitive current input
(3 mA smallest setting)
Earth Fault Differential Protection
•
Earth fault protection for earthed transformer windings, generators, motors, shunt reactors, or starpoint
formers
•
Short command duration
•
High sensitivity for earth faults within the protected zone
22 SIPROTEC 4, 7UT6x, Manual
C53000-G1176-C230-5, Edition 09.2016