Screw compressor trips due to unplanned interlock shutdown
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I would like to ask the experts here: The screw compressor in my company suddenly stopped operating this morning without any prior signs or alarm alerts. The SIS records only showed \"Compressor stopped due to fault\"; there were no records before that, and it started working normally as soon as it was restarted； At the same time as the screw compressor shut down, the turbine’s speed signal exceeded its range, triggering an interlock shutdown ； Both units share the same SIS cabinet, and the cables run through the same trunking. After inspection, no damage to the cables was found. I earnestly ask all experts to help analyze the cause!
If there is no record, it definitely isn’t a problem with the instrument that caused the shutdown. If the instrument triggers the interlock and causes a PLC shutdown, there will definitely be a record of it. If there is no record, it’s definitely an electrical issue. For example, issues such as leakage current or loss of a phase will cause an immediate shutdown; no records are kept in such cases.
Do not draw conclusions rashly without uncovering the truth. The generator in our facility tripped twice in succession; the ETS received signals indicating generator failures that caused tripping, while the electrical protection system indicated turbine failures that led to tripping and subsequently issued a shutdown signal. I searched for several days with no results. It was ultimately found that the mistake was caused by an improper setting of the DCS stator coil temperature interlock value, along with a lack of relevant records.
The overspeed protection of a turbine usually triggers interlocking when the speed reaches 3 times the set value; is this the case here? There are no records of adjustments to the screw compressor; check whether the electrical connections are loose.
It is the case that immediately after the screw compressor shuts down, all three of the turbine speed meters exceed their range, triggering an interlock shutdown
It’s probably not a problem with the interlock system; there were no alarm records before the screw compressor stopped operating. The turbine stopped due to its speed suddenly exceeding the set limit, and there was nothing wrong with the interlock values either
Has the cause of the turbine speed exceeding the range been identified? Is it indeed due to a high rotational speed, or is the high reading caused by some other reason?
If that’s the case, the electrical system should be checked carefully to identify the various situations that could cause the vehicle to stop running; it’s advisable to examine the relevant records from the electrical control system as well.