In this lesson, we're going to discuss
power distribution systems.
Power distribution systems are crucial
for ensuring consistent
and reliable power delivery for our networking equipment,
infrastructure, and environments.
Power distribution systems encompass several key items
that you need to understand to properly manage
and distribute electrical power within your data centers
and network infrastructures,
including an uninterruptible power supply,
a power distribution unit, a generator,
managing your power loads, and understanding
your voltage considerations.
First, let's talk about an uninterruptible power supply.
An uninterruptible power supply, also known as a UPS
or an UPS, is an electrical apparatus
that provides emergency power
to a load when the input power source or main power fails.
Most people think of these as battery backups,
but in our data centers
and telecommunication closets, we usually use devices
that contain more than just a battery backup.
For our purposes, we're usually going to use
an uninterruptible power supply.
It's going to also provide line conditioning
and help protect us from surges and spikes in power.
The goal in using an UPS is to provide us with clean
and reliable power.
Now, an UPS is great for short duration power outages
because they can usually last around 15
to 30 minutes depending on the amount of electrical load
that you're making them support
because they are limited to a relatively short battery life
inside of these UPS devices.
Now the good news is that batteries are getting better
and better every day, and their lives
are getting longer and longer in our newer units.
Generally, most data centers are going to place
a single UPS unit at the bottom of each rack,
and that way they can provide emergency power to any systems
or networking equipment being hosted within that rack.
Some larger data centers have also begun
using larger UP systems that can support multiple racks
at once or even the entire data center
if that data center has a whole room
battery backup system installed.
But remember, these are very expensive,
and you're going to find that they're less common in most small
and medium-sized office environments due to the large cost
of installing these units.
Second, we have power distribution units.
Now, a power distribution unit, also known as a PDU,
is a specialized device for distributing electric power
to various network components and computing equipment.
These are essentially advanced power strips
that are often equipped with power monitoring,
control features, and other things that allow
for the efficient distribution
and management of power across multiple devices
and multiple racks.
A PDU can either be rack mounted in a single rack enclosure
in a smaller organization, but in larger data centers.
You may also see these as large cabinets
where there's one PDU installed for each row of servers
or networking racks.
These power distribution units are designed
to provide power protection from surges, spikes,
and under voltage events,
but they're not designed to provide full protection
against a complete power loss like an UPS mite.
Generally, A PDU is going to be combined with an UPS
or a backup generator to ride power
during a complete power failure event.
This brings us to our third thing we need to talk about,
which is generators.
Now, large generators are usually installed outside
of a data center in order to provide longer term power
during a power outage in your region.
These generators can be either powered by diesel, gasoline,
or propane depending on which one you buy.
For example, at my office,
we have an older 20,000 kilowatt diesel generator
that's used to provide power
to our offices in case of a power outage.
Now, the challenge with using a generator though
is that it takes a little bit of time to start it up
and get it up to speed
before it's ready to provide power to your data center.
For this reason, they're usually going to be paired
with a battery backup or an UPS unit
then when they're being designed
as part of your power redundancy solution.
For example, at our office, if the power goes out right now,
the UPS is going to carry the load for about 15 to 20 minutes.
During that time, our generator will automatically
be brought online, and this will usually take about
60 to 90 seconds.
Once that generator is fully online
and ready to take on the load, all
of our power will be shifted from the UPS as battery
over to the generator using an automatic transfer switch.
Now, once power has been restored in our area
for at least five minutes by our power company,
then our automatic transfer switch will shift the power back
to the electrical grid via that UPS unit,
and then it will issue the shutdown command to our generator
to place it back in a standby mode
where it's rated takeover the next time
a power outage occurs.
The fourth thing we want to consider is
how we're going to manage our power loads.
Now, managing power loads is critical
in preventing circuit overloads
and ensuring efficient power usage
inside of our data centers.
Proper load balancing will ensure
that the power supply is evenly distributed
and that no single circuit is under excessive load,
which could in turn lead to outages or hardware damage.
To support this, our data centers
are usually going to have somebody assigned
to carefully calculate and monitor the power loads on each
and every one of our circuits to avoid overloading them
and to try to optimize our power usage
for the most efficiency.
Now, if somebody wants to install a new piece
of networking equipment into our data center,
like a new appliance, a new server,
or a new switch, that person is going to be assigned
to calculate the impact of adding that new piece
of equipment based on its projected power utilization.
And then we're going to recommend which rack it needs
to be installed in to properly balance out the loads
across the entire data center.
Now, fifth, we have
to think about our voltage considerations.
Voltage refers to the electric potential difference,
and it's a key factor in our power distribution systems.
Now here in the United States where I live, we use 120 volts
as our standard voltage, but over in Europe,
they use 230 volts as their standard.
So if I order a piece of equipment
from a European manufacturer located in Germany,
I need to check if it's going to be able
to be supported by the standard 120 volt power
that we have here in the United States.
Similarly, if somebody over in Europe orders a component
from the United States, they need to verify
that it's going to operate properly on their 230 volts systems.
For example, if I ordered a new server
and it came with a 230 volt power supply,
it simply is not going to power on if I connected
to 120 volt electrical outlet in my US-based data center.
Now, while this is unfortunate,
it's actually not going to hurt that piece of equipment,
and instead, I can simply purchase a transformer
to convert my lower voltage 120 volt power source
into a 230 volt power source that that piece
of equipment can then utilize.
On the other hand, if somebody in Europe doesn't think
to check the power requirements on a new piece of hardware
that they bought from the United States,
and they plug that piece of equipment in
and they expect it's going to get 120 volts like it does here
in the United States, well, guess what's going to happen?
That piece of equipment is going to be damaged badly
because it's going to be receiving 230 volts
from the European electrical socket in that data center
instead of the 120 volts it's expecting.
This can actually destroy the device,
or it can even cause it to catch fire
due to the voltage mismatch that's occurring.
Now, luckily, most devices these days are considered
to be dual voltage and they can be configured
to operate either at 120 volts or 230 volts,
or they'll automatically switch
between the two based on what you have there.
Now, this all depends on the equipment you're using,
but it is something you need to consider
to ensure your network equipment operates optimally
and maintains this longevity.
So remember, when you're designing your data centers,
you need to consider how you're going to distribute
and maintain power throughout the entire data center.
You may opt to install a UPS in each of your racks
to provide power in case of a short-term power loss,
but you're probably also going to want to install a PDU
and a backup generator as well, so you can continue
to operate for the long-term regardless of whether
or not there's a power outage occurring or not.
Also, don't forget to consider the power loads
that you're going to be installing with any new piece
of equipment, and you should always consider the voltage
required by your equipment before you install it
and connect it to your data center's power source.