Probabilistic investigations on bit error ratio requirement for digital teleprotection employing digital microwave links

The authors describe a bit error ratio (BER) requirement for a pulse-code-modulation current differential teleprotection system employing digital microwave links. Assuming random errors in the microwave communication channel, relay downtime ratio due to errors or relay lock ratio was evaluated. To meet an existing relay lock ratio in an FM current differential teleprotection system with analog microwave links, a threshold BER to determine the propagation path unavailability should be 10^-7 to 10^-6. The teleprotection system unavailability is also discussed