•
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)
Time Overcurrent Protection for Earth Current
•
Two definite time delayed overcurrent stages for the earth current, e.g. current between starpoint and
earth
•
Additionally, one inverse time delayed overcurrent stage for the earth current
•
Selection of various inverse time characteristics of different standards is possible, alternatively a user
defined characteristic can be specified
•
The 3 stages can be combined as desired
•
External blocking facility for any desired stage (e.g. for reverse interlocking)
•
Instantaneous trip when switching on a dead fault with any desired stage
•
Inrush restraint function with 2nd harmonic
•
Dynamic switchover of the time overcurrent parameters, e.g. during cold-loaded start-up of the power
plant
•
2 time overcurrent protection functions for earth current possible (only 7UT613/63x)
1-phase Overcurrent Protection
•
Two definite time delayed overcurrent stages which can be combined as desired
•
For any 1-phase overcurrent detection
•
Can be assigned to the “normal” 1-phase current input or to the highly sensitive current input
•
Suitable for detection of very small current (e.g. for high-impedance unit protection or tank leakage
protection)
•
Suitable for detection of any desired AC voltage using an external series resistor (e.g. for high-impedance
unit protection)
•
External blocking facility for any stage
Unbalanced Load Protection
•
Evaluation of the negative sequence system of the three phase currents of any desired side of the
protected object or any three-phase measuring point
•
Two definite time delayed negative sequence current stages and one additional inverse time delayed
negative sequence current stage
•
Selection of various inverse time characteristics of different standards is possible, alternatively a user
defined characteristic can be specified
•
The stages can be combined as desired
•
Trip blocking on detection of broken wire
•
Thermal characteristic with adjustable negative sequence factor and adjustable cooldown time
Thermal Overload Protection
•
Thermal replica of current-initiated heat losses
•
True RMS current calculation
•
Can be assigned to any desired side of the protective object
•
Adjustable thermal warning stage
•
Adjustable current warning stage
Introduction
1.3 Characteristics
SIPROTEC 4, 7UT6x, Manual 23
C53000-G1176-C230-5, Edition 09.2016
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