Wireless Networks and Power Quality
Will installing wireless networking change my back-up power requirements?
What data do I need to know in order to
determine my wireless network back-up power requirements?
What other issues should I consider when sizing/selecting power quality equipment?
What are some of the new back-up power
products and ideas available to help with the
issues?
Wireless Networks and Power Quality
Will installing wireless networking change my back-up power requirements?
Most likely yes for the following reasons.
Wireless Networks and Power Quality
Wireless Access Networks use
approximately (5) - (10) times the power per user.
Baliga, et al., “Energy Consumption in
Wired and Wireless Access Networks”,
IEEE Communications Magazine, June
2011, pp 71-77.
Wireless Networks and Power Quality
Wireless Networks have distributed
back-up power requirements.
Units requiring
back-up power will
be spread through
the buildings as
well as between
buildings
Wireless Networks and Power Quality
Wireless devices do not detect
power failure of
access points or
remote modems
very quickly.
Wireless Networks and Power Quality
Back-up power for
wireless network
devices will require
long run times or
generators in order
to support voice,
PDAs, monitoring,
security and other
possibly unexpected
critical applications.
Wireless Networks and Power Quality
PDAs and Smartphones insure that nearly every network will support some voice
applications.
Point to point wireless to bring data, phone, monitoring and security to remote buildings
and/or locations is one of the main reasons to install wireless at many locations.
New wireless devices are being introduced for
retro-fitting in order to support new regulations
and enhance life safety at facilities.
Wireless Networks and Power Quality
What do I need to know in order to determine my wireless network back-up power
requirements?
Basically, you need a plan.
There is no one right answer but there are some basic steps to follow. It helps if you have a
power distribution strategy when designing the
network.
Wireless Networks and Power Quality
Step 1: Power Distribution Strategy
Identify rooms/closets, equipment in the closets and the point to point connection between
closets.
Determine a “network closet/server room” UPS strategy.
Determine the type and rating of power
available in each room. For example 208-120V,
3PH+N+G, 200A.
Wireless Networks and Power Quality
Step 1: Power Distribution Strategy
Determine how to get back-up power to devices remote from the rooms.
AC power feeds from the room UPSs.
– Lower UPS, switch and battery cost.
– Easier to provide UPS redundancy.
– Do not have to maintain remote batteries.
– High wiring infrastructure cost.
Wireless Networks and Power Quality
Step 1: Power Distribution Strategy
Determine how to get back-up power to devices remote from the rooms.
POE power feeds from the room UPSs.
– Lower UPS, switch and battery cost.
– Easier to provide UPS redundancy.
– Do not have to maintain remote batteries.
– Distance limitation is 300ft maximum.
– Lower infrastructure wiring cost.
Wireless Networks and Power Quality
Step 1: Power Distribution Strategy
Determine how to get power to devices remote from the rooms.
Dedicated UPS.
– Higher UPS and battery cost.
– UPS redundancy more difficult.
– Remote batteries complicate maintenance.
– Infrastructure wiring cost is lower.
– It can be difficult to find a location for the UPS.
Wireless Networks and Power Quality
Step 2: Inventory and Categorize Loads
Put together a list of every device in the network and its power requirements average power,
average KVA and Peak KVA. Include server loads and other loads if using a common UPS.
Determine which loads need to be on stand-by power.
Divide them into load centers by location.
Determine minimum runtimes for each device.
Wireless Networks and Power Quality
Step 2: Inventory and Categorize Loads
Breakout devices with long runtimes from short runtime devices. Only size your generator or extended battery packs for devices requiring a long runtime.
Determine the layout of UPSs and modify
network designs if necessary to accommodate distribution.
Make a physical layout of the devices if
necessary.
Wireless Networks and Power Quality
Step 3: Configure, Size and Select UPS
Identify loads by UPS
Identify available power for connecting the UPS
Identify UPS runtime requirements.
Identify redundancy requirements.
Identify spare capacity and growth requirements.
Calculate the required UPS power and select
the UPS model.
Wireless Networks and Power Quality
Case Study: Industrial Systems Integrator Original:
- One building with shop.
- Battery backed VoIP Phone System.
- Servers and hardwired network switches/router on back-up power. Servers/Switches are (10) minutes (1200W) and network router is 30 minutes (100W) - Only wireless is ad hoc WiFi routers through out the
offices and shop.
- One data closet with servers and network switches.
Wireless Networks and Power Quality
Case Study: Industrial Systems Integrator New:
- Two buildings separated with by 1/8 mile and road with two main data closets one in each building.
- Point to Point wireless to provide voice, data and security in the new building.
- Wireless Point to Point and Switches/Routers supporting VoIP require (60) minutes of battery back-up
- Servers and Office/Shop Network both (wireless and wired) require (10) minutes of battery back-up.
- Wireless Access Points to be POE connected. Wireless
access to be available in all office and shop areas.
Wireless Networks and Power Quality
Case Study: Industrial Systems Integrator Network Power:
- Main Data Closet UPS to support 250W proxy
server, 150W point to point radio modem, and 90W WAN modem/switch. Requires (60) minute runtime.
- One UPS to support (2) legacy data servers (750W), data switches (150W) and (3) new POE switches for new access points in the main building offices
(1100W). Each new switch supports (12) Wireless Access Points (25W each). Requires (10) runtime.
- One UPS to support new POE switch with (9)
wireless access points for the shop/outdoor wireless.
Wireless Networks and Power Quality
Case Study: Industrial Systems Integrator Network Power:
- New Building Data Closet UPS to 150W point to
point radio modem, and POE 200W network switch (phones and link). Requires (60) minute run time.
- One UPS to support new POE switch with (12)
wireless access points for the office/shop/outdoor
wireless. (400W with 10 minute run time)
Wireless Networks and Power Quality
Case Study: Industrial Systems Integrator Network Power:
- Total of (5) UPSs.
- UPS #1 - 490W nominal load - 60 minute run time
- UPS #2 - 2000W nominal load - 10 minute run time
- UPS #3 - 250W nominal load - 10 minute run time
- UPS #4 - 350W nominal load - 60 minute run time
- UPS #5 - 400W nominal load – 10 minute run time
SIMPLIFIED DIAGRAM
Wireless Networks and Power Quality
UPS #1
UPS #2
UPS #3
Switch #1
Switch #2
WAN VoIP PBX
Radio Radio
Switch #6 UPS #4
Switch #7 UPS #5 Switch #3 APs
APs
APs
MAIN BUILDING SATELLITE
Switch #4
Switch #5
Phones
Wireless Networks and Power Quality
What other issues should I consider when sizing/selecting power quality equipment?
Add 5% power loss for POE connected equipment.
Determine a power factor. Around 0.93 leading is typical for server and network equipment power supplies. Make sure the UPS can handle leading power factor and the meet both kW and KVA loading requirements.
Account for largest peak load of a single device in the KVA.
After accounting for the above factors, size the UPS for 50% to 70% loading to allow for future expansion.
If the UPS has a modular battery system, size the batteries,
based on average load including expected POE losses.
Wireless Networks and Power Quality
What other issues should I consider when sizing/selecting power quality equipment?
What type of UPS is required? Double Conversion, Line Interactive or Passive Standby. Minimum acceptable
efficiency?
What type of power is available? Voltage, Frequency and Phases.
Will the UPS require a transformer?
Hot Swappable Batteries
Bypass switch configuration
