Analysis of the causes of abnormal noises during the operation of centrifugal compressors
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At 23:16:28 on August 25th, the shift supervisor in the control room heard an abnormal noise coming from the centrifugal compressor in the octane unit; the noise lasted for a short period of time, about 2 seconds. After the noise occurred, it was observed through the DCS that the operating current dropped to 0 amps at 23:16:28, and then returned to normal levels at 23:16:30. During this time, no abnormal changes were detected in the compressor’s operating parameters (shaft displacement, shaft vibration, speed, frequency) nor in the process parameters (inlet and outlet pressures). The electrician checked the power supply lines and found no issues with voltage fluctuations, and the instruments showed no signals indicating a shutdown due to interlock systems. This phenomenon is similar to what happens when there is a change in the power supply. Experts, please help analyze this situation – what could be the reasons behind the current dropping to 0 amps?
The cause of the voltage fluctuation is likely an issue with the electrical system, such as a temporary circuit break.
The possibility of electrical interference has been ruled out; it is estimated that the issue is related to poor contact with the current detection signal or the circuit board, resulting in the detected current being a false signal.
False signals are possible; it’s best to have the electronic control system checked.
It shouldn’t be a problem with the current detection circuit. If it is only a false signal detected by the current, there should be no \"unusual noises from the centrifugal compressor of the octane unit heard in the office\". Since the abnormal noise is so noticeable, there must indeed be a problem with one of the circuits. By the way, how is the operating current of DCS measured? Is three-phase current or single-phase current being collected?
It’s possible there is a problem with the instrument signal
1. The remote signal is incorrect, resulting in a current of 0. The abnormal noise duration of the centrifugal compressor is short, around 2 seconds, yet there are no changes in the compressor’s parameters or even in the inlet and outlet pressures, which is contradictory.