Handling the fire alarm system in the coking unit caused a black screen of the DCS and full interlock of the SIS
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A few days ago, the fire alarm system of the unit kept giving false alarms. The instrumentation team was called in to handle the issue; during their attempts to fix it, they disconnected the power supply to the fire alarm system. As a result, the entire DCS system of the unit went dark, and the SIS system also stopped working. This triggered automatic interlocks in the heating furnace, the feed pump for the heating furnace, and the air compression unit. The feeding to the heating furnace was interrupted, the furnace stopped operating, and the air compression unit ceased functioning as well. Currently, while the Operations Department is organizing personnel to analyze the reasons, the workshop still does not understand why handling the fire alarm system caused the DCS to go dark and all SIS systems to enter interlock mode. I wonder if any coking plants have experienced something like this. Please discuss. This post was last edited by Chengbei Zhibei on 2009-3-10 21:44.]
Was it the interruption of power to the fire alarm system that caused the DCS engineer station to lose power and shut down, resulting in a black screen on the DCS as well as the activation of all interlocks in the SIS? This post was last edited by Bai Ding on 2009-3-10 22:35]
Was it the case that when trying to cut off the power to the fire alarm system, an accidental action led to the shutdown of the DCS power supply or the main power supply, and they didn’t dare admit it, so they had to make excuses? Or it may be a design flaw: the power supply for the fire alarm system, namely the DCS power supply, is connected via a single circuit, which results in a power outage of the DCS power supply, a black screen, and full interlock of the SIS system.