The recent IPS ENEL outage occured Saturday the 3rd of April forced some systems to shut-down. Automatically, of manually for safety reasons.
As visible in the plot (right down image, the three currents of the CEB UPS line), there were current "spikes" in phase "S" before the IPS ENEL outage.
These spikes are of a device that activates every two hours, and only for 19 seconds. Everyday. And it is powered by one of the three UPS phases only.
It sinks a current of about 3Arms, therefore is a device of about 700VA
This device is potentially "dangerous", because when activated it creates many sidebands in the UPS power line, and these are seen also in the CEB magnetometers.
From past experience, we know that having this type of noise could be a problem in Hrec (we have seen this with many other devices).
This periodic noise has come back three days later, Tuesday morning, around 9:30 LOCAL TIME (maintenance period). Probably with a manual action done for recovering from an automatic switch off.
Have someone did something at that time? Has any devices (maybe some chiller) been turned ON again just before that time?
Please report to the ENV group any action.
I would change the last sentence in:
Please, report ON THE LOGBOOK any action.
I asked Davide, and he told me that he switched ON the AHU at 08:57 LT of Tuesday April 6th. (it remained OFF at the time of the ENEL problem, and Davide forgot to switch it ON the morning after...).
In the attached plot the effect of the power ON is clearly visible.
In agrement with the Control Room and Davide, I then turned OFF the AHU on 09-04 at 14:24 UTC, and turned it back ON today at 08:50, by turning ON the same general switch (labeled E1) on which Davide had operated.
From the attached plots it can be seen that glitches are also present during the shutdown period.
Therefore, the device that is producing the glitches is something else.
It is worth mentioning that in the period 09:03 - 09:33 UTC the UPS_CURR_S was lower, as the lights of the L-shaped corridor adjacent to the DET area were OFF.
