322 MW STG unit experienced trip subject to sudden closure of dual MSV & CV lines without any trip event record from L40 CKT for M6E or any other trip signals.
Sequential trip occured subject to sudden closure of Steam valves (MSV1,2, CV1,2)
1) MSV-1/2 closed and CV-1 & 2 also closed and opened event trend observed 2) Event in Live trip data server.
2)ST16 - CONTROL VALVE TRIGGER OCCURRENCE - LCVT_EVT â€" ALARMED and ST16 - CONTROL VALVE TRIGGER OCCURRENCE - LCVT_EVT â€" NORMAL
3) ST16 - Hyd Fluid Pump #1 Running-Closed When Running - l63hq1_run [PDIO-45Contact09] - ALARMED
[This signal is derived from pressure switch (PS-280B) of pump #1 discharge pressure monitoring, when pressure going below 161.7 Kg/cm2 this alarm will generate.]
4) As part of sequential trip configuration for 9FA occured as Steam valve closed/Limit switches closed reseluted for pick up of -33ST-33STX-32-1,2 GCB OPEN from GPP-generator protection panel.
Kindly let us know any of the sites experienced similar trip in ST units. Appreciate experts to share their experiences in fleet.