Too bad...

We know we have to work on holydays....
But when you are on duty for trouble-shooting service you might be called....
Martin, here on top of the main transformer of unit EC4 was the lucky guy today!

We had to call him because we recieved a low-pressure alarm on the main high-voltage switchgear. We use SF6 gas as a kind of insulating gas in the switchgear, thus reducing the size of the switches; it insulates a lot better then air.
We call it "extinguish gas" because it reduces the flames when the switches open.
In the so-called "Tripping matrix" we could see the unit trips when the pressure would reach the treshold one step below this alarm. The unit is at standstill so we had to take action. We would have had to explain something when the unit might have tripped tomorrow after going on the grid and we had done nothing. And: we learn every day because we don't do this every day.
The switches connect the outlet of the main transformer to the 220 KiloVolt grid. (the red cable going down)

Here in LARGE

Here is another view.