Control functions
Control and monitoring functions
Several predefined functions are implemented:
- activation of multiple set point profiles
- remote reset
- CT and VT monitoring
- logic selectivity
- cold load pickup (CLP)
- automatic reclosing (79)
- trip circuit supervision (74TCS)
- stabilization during tranformer energization (INRUSH)
- synchronisation
- CB control and monitoring.
Self test diagnostic
The run-time testing feature ensures that the relay will provide proper and reliable protection.
Main checks concern:
- power supply
- output relays coils
- CT and VT secondary
- blocking circuit (breaks or short circuits on the pilot wires)
- non-volatile memory
- circuit breaker status
- watchdog
- data base and communication CRC.
Programmable logic
User defined logic must be customized in accordance with the IEC61131-3 protocol. The logic may complete or replace the supervision functions normally included in the switchgear control and executed by programmable logic controllers (PLC).
In addition to the elementary logic (OR, AND, NOT, XOR,...), further functional blocks are supported:
- timers
- sequential logic (flip-flops...)
- counters
- comparators
- selector switches.
Each trigger can be set on positive/negative transition of events or binary inputs.
IEC61131-3 standard intrinsically introduces the software quality concepts in relation to:
- comprehensibility
- reusability
- testability
- maintainability
- life cycle
- fault identification.
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