Siemens SIPROTEC 7SJ80

Undervoltage-controlled reactive power protection (27/Q)
•
Detection of critical power system situations
•
Disconnection of power supply facilities from the grid
•
Reconnection under stable power system conditions
Thermal Overload Protection 49
•
Thermal profile of energy losses (overload protection has full memory capability)
•
True r.m.s. calculation
•
Adjustable thermal warning element
•
Adjustable alarm level based on current magnitude
Monitoring Functions
•
Increased reliability due to monitoring of the internal measurement circuits as well as the hardware and
software
•
Fuse failure monitor with protection function blocking
•
Monitoring of the current transformer and voltage transformer secondary circuits using sum and
symmetry supervision with optional protection function blocking
•
Trip circuit monitoring possible
•
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
•
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
•
For inverse-time overcurrent protection, a user-defined characteristic is available
•
Direction determination with zero sequence quantities(Ι
0
, V
0
), wattmetric ground fault direction determi-
nation
•
Any element can be set as directional or non-directional — forward sensing directional, or reverse
sensing directional
•
Optionally applicable as additional ground fault protection.
Intermittent Ground Fault Protection
•
Detects and accumulates intermittent ground faults
•
Tripping after configurable total time.
Directional intermittent ground fault protection
•
Detects intermittent ground faults
•
Direction determination
•
Tripping after settable number of intermittent re-ignitions
Introduction
1.3 Characteristics
26 SIPROTEC 4, 7SJ80, Manual
E50417-G1140-C343-A8, Edition 12.2017