Siemens siprotec SJ62 User Manual page 33

1 Introduction
Intermittent Ground
Fault Protection
Automatic Reclos-
ing 79
Fault Location
Breaker Failure
Protection 50 BF
Flexible Protection
Functions (7SJ64
only)
Synchronism and
Voltage Check 25
(7SJ64 only)
31
• Detects and accumulates intermittent ground faults;
• Tripping after configurable total time.
• Single-shot or multi-shot;
• With separate dead times for the first and all succeeding shots;
• Protective elements that initiate automatic reclosing are selectable. The choices
can be different for phase faults and ground faults;
• Different programs for phase and ground faults;
• Interaction to time overcurrent protection element and ground fault elements. They
can be blocked in dependence of the reclosing cycle or released instantaneously;
• Synchronous reclosing is possible (only 7SJ64) in conjunction with the integrated
synchronizing feature.
• Initiation by trip command, external command or dropout of pickup;
• Fault distance is calculated and given in secondary ohms and miles, or kilometres.
• Checking current flow and/or evaluation of the circuit breaker auxiliary contacts;
• Initiated by the tripping of any integrated protective element that trips the circuit
breaker;
• Initiation possible via a binary input from an external protective device;
• Initiation possible via the integrated control function.
• Up to 20 protection functions which can be set individually to operate in three-phase
or single-phase mode;
• Any calculated or directly measured value can be evaluated on principle;
• Standard protection logic function with definite time characteristic;
• Internal and configurable pickup and dropout delay;
• Modifiable message texts.
• Verification of the synchronous conditions before reclosing after three-pole tripping;
• Fast measuring of the voltage difference ΔV, the phase angle difference Δϕ and the
frequency difference Δf;
• Alternatively, check of the de-energized state before reclosing;
• Switching possible for asynchronous system conditions with prediction of the syn-
chronization time;
• Settable minimum and maximum voltage;
• Verification of the synchronous conditions or de-energized state also possible
before the manual closing of the circuit breaker, with separate limit values;
• Measurement also possible via transformer without external intermediate matching
transformer;
• Measuring voltages optionally phase–to–phase or phase–to–ground.
SIPROTEC 4, 7SJ62/63/64 Handbuch
C53000-G1140-C147-A, Edition 07.2015