Issues regarding the interlock shutdown of the TRICON unit control system

Thread Content

Hello everyone, an abnormal incident has occurred in Unit 1 of our plant: the cyclic hydrogen compressor stopped suddenly. The control system used is TRICON. According to the SOE records, fault alarms were triggered simultaneously for the vibration and displacement signals of all compressors and turbines at the time of shutdown – faults occurred due to currents exceeding the permissible levels. Ultimately, the shutdown was initiated as a result of excessive displacement (a displacement of -1 mm in an open-circuit condition triggered the interlock). Then these fault signals return to normal automatically after one scanning cycle (200ms). These signal points enter two separate AI cards, and the circuit power supply is also configured redundantly. No cause has been found yet for the simultaneous failure of the 8 vibration signals and 4 displacement signals; it is initially suspected that a sudden drop in the power supply voltage led to it falling below the operating voltage of the preamplifier, resulting in an open circuit. But can the voltage fluctuations recover within one scanning cycle? I hope fellow sailors can help analyze the possible reasons. Thank you.