Thermal Overload Protection 49
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Thermal profile of energy losses (overload protection has full memory capability)
•
True RMS calculation
•
Adjustable thermal warning element
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Adjustable alarm level based on current magnitude
•
Additional time constant setting for motors to accommodate the motor at standstill
Monitoring Functions
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Increased reliability due to monitoring of the internal measurement circuits as well as the hardware and
software
•
Voltage transformer monitoring with protection function blocking
•
Broken conductor detection
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Monitoring of the current transformer and voltage transformer secondary circuits using sum and
symmetry supervision with optional protection function blocking
•
Inrush current detection with 2nd harmonic for directional and non-directional overcurrent protection
•
Phase rotation check.
Ground Fault Detection 50N(s), 51N(s), 67N(s), 59N/64
•
Displacement voltage is measured or calculated from the three phase voltages
•
Determination of a faulty phase on ungrounded or grounded systems
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Two element ground fault detection: 50Ns-1 and 50Ns-2
•
High sensitivity (as low as 1 mA)
•
Overcurrent element with definite time or inverse time delay
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For inverse time overcurrent protection, characteristics according to IEC or ANSI standards and a userde-
fined characteristic are available
•
Direction determination with zero-sequence quantities (I0, V0), watt-metric ground fault direction deter-
mination
•
Sector characteristic settable as directional characteristic
•
Any elementcan be set as directional or non-directional — forward sensing directional or reverse sensing
directional
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Optionally applicable as additional ground fault protection
Automatic Reclosing 79
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Single-shot or multi-shot
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With separate dead times for the first three and all subsequent shots
•
You can configure which of the overcurrent protection elements work with automatic reclosing and
which not
•
Separate programs for phase and ground faults
•
Interaction with the time overcurrent protection elements. These can be blocked depending on the
reclosing cycle or trip instantaneously.
Sectionalizer
•
Have no capacity to break the fault current
•
Isolate the fault current sections of a distribution circuit only when an upstream breaker or recloser has
interrupted the fault current.
Introduction
1.3 Characteristics
SIPROTEC Compact, 7SC80, Manual 29
E50417-G1140-C486-A8, Edition 07.2017
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