There are several different layers that contribute to keeping our racks diversely powered at all times.   Every layer is just as important as the last.  One of the biggest contributors to power in a data center is the substation.

The substation actually feeds power to the data center from the utility company.  It is important that we know where it is located.  Is it onsite and dedicated to the facility or is it miles away?  We want to know this in case there is a natural disaster so that we know if our substation, that is feeding power to our rack, is affected.  Another thing that we should look into is how the substation is fed.  The preferred way is to have diverse power generating sources going into the substation.

Diverse-Power-SchematicNext, we look to see that, from the substation, there are diverse power entries into the building into diverse generator distribution panels.  The more diversity the data center has the better.  From there, there should be both an A side and B side diesel generator.  The best thing about having A side and B side generators is that it allows any portion of the chain to fail without our rack losing power in anyway.

There is even more protection than the “A” side and “B” side generators.  If there is for any reason a utility outage, the generators would power on. While the generators are powering on the uninterrupted power supplies or UPSs would turn on to hold the load.  As soon as the generators are up and running and are supplying power, the UPSs turn back off and go back to being charged.

From the UPSs, we get to our rack.  The “A” side UPS goes to our “A” side power distribution unit or PDU and the “B” side UPS goes to our “B” side PDU.  So, ultimately our rack will never lose power.

So, to recap, we want diverse power to the substation and to the distribution panel with two generators that are supplying diverse UPSs that are ultimately supplying diverse power to the PDUs within our rack.  We want to make sure that our data center has all of these levels of power to ensure that our most valuable asset is always accessible.