Transcript
zPDS: High Rack Power Densities zPDS™ is the Power Distribution System that delivers a flexible range of redundant, High Rack Power Densities. Its innovative “at-the-rack” functionality simplifies the distribution of redundant 3 phase power and has a number of added advantages including simplifying power reconfigurations as well as time and financial benefits. What are the advantages of distributing 3 phase AC power to the rack? In a three phase system, three circuit conductors carry three alternating currents of the same frequency which reach their instantaneous peak values at one third of a cycle from each other. Three phase power distribution is the standard for power distribution in electrical grids worldwide due to its transmission efficiency. It is also more efficient and flexible to distribute three phase to the rack as single phase is easily derived from 3 phase at the rack, but not the reverse. Three phase power distribution uses less conductor copper (or aluminum) for transferring the same amount of power as compared to single phase power. As a result, three phase distribution delivers the most power out with the least copper required for whips and that makes it less expensive to deploy. Additionally, higher voltages can be transmitted with three phase resulting in lower amperages. For example, given a rack with a 5-10 kVA load, with three phase, you would need 15-20 amps per phase while you would need 50 amps with single phase which requires more copper and has a higher deployment cost. Utility supply to the data center service entrance is typically 480V three phase used by most UPS systems. Data centers are deploying three phase power to the rack as rack power densities grow due to increasingly power-hungry devices and eventually, 3 phase may be the only option available to meet higher rack power densities. How does zPDS deliver maximum redundant power density? Maximum redundant power density is achieved as follows. Considering only the “A” side of the zPDS, distribute a 3 phase power whip to a zPDS with 480V/3ϕ and a maximum amperage rating of 60 amps. Connecting two, 3 phase plug strips to the zPDS output, the zPDS delivers a maximum of 40kW distributed to 2 racks or 20kW per rack. Note this is only the A side. Duplicating this on the B side of the zPDS provides a redundant “B” backup in case the “A” power source goes down. Alternatively, if redundancy is not required, the B side of the zPDS can power 2 additional racks at 20kW per rack. Most data centers require power redundancy so the typical deployment of zPDS is 2 racks at 20kW per rack with A-B power redundancy. The math looks like this:
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zPDS 1 Gen
480V/3ph ÷ (√3 = 1.732) = 277V/1ph x 30A x 3 phase x 2 receptacles x 80% (20% de-rate) = 39.9kVA.
The zPDS also has input options of 415V/3φ and 208V/3ϕ. As a result, the maximum redundant power density in each of 2 cabinets is 20kW, 17.2kW or 8.6kW for input voltages of 480V/3ϕ, 415V/3ϕ, or 208V/3ϕ respectively.
zPDS 2
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Additionally, zPDS has an option for three redundant outputs to drive three, 3 phase plug strips. In this case, the maximum redundant power density is distributed over 3 cabinets and the maximum redundant power density in each of 3 cabinets is 13.3kW, 11.5kW or 5.7kW respectively for input voltages of 480V/3ϕ, 415V/3ϕ, or 208V/3ϕ. Note, in the above discussion assumes 1kVA = 1kW and assumes the power factor is 1.0. Today’s IT equipment power supplies are typically 0.98; close enough for this assumption. How does this compare to other power distribution methodologies? Distributing 3 phase power whips directly to 3 phase plug strips in the rack. This method utilizes all the available power but requires a separate power whip for each 3 phase plug strip. For the case of 3 cabinets with redundant power, connecting whips directly to 3 phase plug strips requires 6 whips and 18 PDU breaker positions while zPDS requires only 2 whips and 6 PDU breaker positions. Additionally, zPDS eliminates the need to pull more whips with equipment changes or power reconfigurations as they can be done at the rack using adaptor cables. zPDS also provides the advantage of a circuit breaker for each phase of each output.
zPDS: High Rack Power Densities How does zPDS simplify the management of power reconfigurations? zPDS simplifies the management of power reconfigurations by making the cabinet the locus of power reconfigurations. The zPDS outputs are four NEMA L21/22-30R receptacles or six NEMA L21/22-20R receptacles. The zPDS product line includes adaptor cables to connect special equipment such as wiring harnesses for blade servers and other specialty equipment. As power reconfigurations are necessary, changes can be made by using a common or custom zPDS adaptor cable eliminating the risk, the time and the expense of having an electrician pull another power whip and consuming additional PDU breaker positions. What are the added advantages zPDS provides? Circuit Breaker protection on each phase of each output. Depending on the options, zPDS has either 12 or 18 fast acting circuit breakers to protect each phase of each output. This gives the advantage of manually turning off selected devices within a rack for maintenance while leaving the remainder of the equipment powered on. Additionally, if an over amperage condition occurs, only a portion of the equipment is powered off rather than the whole rack. zPDS breakers are thermo-magnetic with Curve 62 and they open before a branch breaker opens. They function accurately and repeatedly. By comparison; most plug strip breakers are thermo-only and will not reliably open before branch circuit breakers. OSHA compliance. OSHA requires de-energizing any whips involved in re-cabling and changes. There is inherent risk to personnel, equipment and customers with the current practice of making hot-changes and re-cabling changes without de-energizing the whips involved. zPDS is OSHA compliant and future-proofs your data center. zPDS provides the advantage of making these changes at the rack with plugs and receptacles. No more hot-changes, and no need to de-energize a whip because changes are made by plugging and unplugging adaptor cables at the rack. This can have wide ranging positive effects on processing, throughput and customer service. “Build-it-once” or “Build-it-as-you-go”: While zPDS can be deployed in areas of existing data centers in a “build it as you go” methodology, it also supports a “build it once” methodology. A “build it once” methodology includes laying out a standard grid of redundant power whips with power receptacles located where present and future equipment is planned to be installed--either under the floor or overhead. The power receptacles are ready to accept a zPDS unit when new equipment is installed. This eliminates or vastly reduces the need to pull additional whips as new equipment is installed or rack populations change. The advantage of a “build it once” methodology is that you plan for maximum power needs where needed and standard power needs throughout the data center. zPDS Advantages and Benefits
Delivers range of redundant, high rack power densities o 2 rack configuration: 8.6kW to 20kW per rack, redundantly. o 3 rack configuration: 5.7kW to 13.3kW per rack, redundantly.
Lowers electrical costs and labor for wiring changes (zPDS uses ⅓ or ½ # whips) o 3 rack configuration: 2 whips for zPDS vs. 6 whips otherwise.
Maximizes available breaker space at PDU (zPDS uses ⅓ or ½ # breakers) o 3 rack configuration: 6 PDU breaker positions for zPDS vs. 18 PDU breaker positions otherwise.
Eases power cable management by reducing whip and cord tangle, clutter and airflow blockage.
Distributes loads evenly across all phases with patented phase rotation technology.
Compatible with all busway, EMT conduit and raceway build outs and power strips in either raised floor or overhead.
Integrates with Starline™, seamless plug and play.
You can view a 2 minute video of zPDS by copying and pasting the following into your web browser: http://www.zonit.com/storage/ric-videos-animation/zonit%20zPDU%20flash%20demo.swf
