• The timing issue seem occurred when the IPS came back

Just to add a bit of information: this is not the ENEL IPS, but our "Diesel engines" generated IPS. The ENEL IPS return after more than an hour (see attached plot for event timing)

The CEB "S" UPS went to zero when starting the Diesel generator. This needs to be better understood (there is no a good reason).

• it s strange to sse that the UPS MC current went to zero during IPS shutdown

This could be explained if the MCB UPS Current sensors electronics is powered with the IPS mains. To be checked.