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?
Will installing wireless networking change my back-up power requirements? Most likely yes for the following reasons.
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 have distributed back-up power requirements. Units requiring back-up power will be spread through the buildings as well as between buildings
Wireless devices do not detect power failure of access points or remote modems very quickly.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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)
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 WAN VoIP PBX UPS #1 Switch #1 Radio Radio UPS #2 Switch #2 Switch #3 Switch #4 APs Switch #6 UPS #4 Phones Switch #7 UPS #5 UPS #3 Switch #5 APs APs MAIN BUILDING SATELLITE
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.
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 Communications
Applying Factors from previous two slides: UPS #2 POE loss is 50W and rated power for battery sizing is 2050W. The expected average kva is 2050/0.93 = 2204VA The peak instantaneous load of a POE Switch is 800VA/720W vs 400VA/375W average and for a Server 700VA/630W vs 320VA/300W so add 400VA/345W for peak load or 2620VA/2395W Sized at 50% for expansion 5.24kVA/4.69kW Sized at 70% for expansion 3.8kVA/3.4kW
Applying Factors from previous two slides: UPS #2 The location has a 240 single phase 30A outlet, (2) 120V single phase 20A outlets and (4) 120VAC single phase 15A outlets available Specify a 4kVA to 6kVA UPS with a 0.9 leading power factor output without de-rating, 240 single phase input (L6-30P), 240/120 Split phase (integral transformer) with a L14-30R and 5-20R output receptacles, a LAN based web server interface and (10) minute runtime at 2050W.
What new product trends are by data/communication closets? Rack mount line Interactive and double conversion 120V single phase UPSs with extended battery modules (0.5kVA to 3kVA) Rack mount 208/220/240V-120 split phase UPSs with extended battery modules (5kVA to 11kVA and high efficiency) Rack mount 208-120V (400-230V) three phase UPSs with extended battery modules (8kVA to 60kVA with high efficiency.) Rack mount power distribution and monitoring.
Single Phase Product Positioning and application overview
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