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Increase the power efficiency of the downstream UPS almost neglected in the past, but today received more attention. With the focus on improving PUE (or last DCiE), the industry recognized, UPS and the UPS itself, the efficiency of the downstream and upstream of the efficiency of the UPS is just as important. Remember, UPS downstream every 1% loss would make PUE increased by 1.2% to 3%.
So, how do we improve the efficiency of the downstream UPS? We will focus on opportunities in three key areas: electricity distribution structure Transformer And voltage.
Electricity distribution structure You should try to remove the UPS
downstream distribution panels (PDU) and remote for Power supply Panel (RPP) on the static bus Switch (STS or SBTS). Apart from some inherent power loss, STS will increase costs, reduce the use of space, reduce the availability (if they become a single point of failure), and increased operational complexity. If the STS is necessary, they should be installed on your computer Cabinets And cabinet power supply device.
At the level , and of the facilities, you should consider redundant PDU (in effect to consider, 2N, or distribution of the system + system) is meaningful. Under normal circumstances, PDU transformer efficiency increases with the load, so the two shared a PDU load, their efficiency will be lower than the same load-bearing efficiency of a PDU. In addition, single-core server power than dual-core server more efficient.
Only two thoughts on the UPS structure. If 2N + system structure or system is needed, you should consider 3N / 2 or 4N / 3 structure as the alternate. Suppose the critical load is 2000kW, a 2N assembly requires two UPS systems, each a capacity of 2000kW. In a 3N / 2 of the assembly, you need three UPS systems, each a capacity of 1000kW. 3N / 2 assembly advantages are as follows:
1, the initial costs are lower, because you are buying a total capacity of 3000kW of UPS, rather than 2N assembly required 4000kW capacity.
2, more efficient operation, because each 3N / 2 system compared with each of 2N system, 3N / 2 system in a higher percentage rate on the run. Fully loaded, each 3N / 2 system will run on 67% rating, while the 2N system will run on 50% rating.
Compared with the 2N system, 3N / 2 or 4N / 3 system's disadvantage is the need for more attention to load management.
Second thoughts on the UPS structure is: Consider the project, the redundancy module UPS system, whether it is meaningful. Redundant module to increase the initial cost and operating costs. An important part of the cost increase is lower redundancy module efficiency.
Transformer UPS downstream transformer is usually loaded on the PDU. You should understand that every time we transform voltage, in the process, we lost 1.5% -3% of energy. Where possible, remove the transformer is an increase Energy Good efficiency technology.
Transformer if you need to consider the use of fewer large transformer, not the smaller transformer. A large capacity transformers are usually small-capacity transformers more efficient. Therefore, it is necessary to specify a smaller number and larger capacity transformer, not the reverse. For example, the Energy Star (EnergyStar ®) of the 75kVA transformer minimum efficiency is 98%, 300kVA transformer efficiency of 98.6% minimum.
You should specify the transformer in its plans to work load efficiency. Consider a normal level assembly, each transformer can be rated at up to 90% of the running: the peak efficiency of 50% should be required to -90% of the ratings. On the contrary, for a level assembly, the peak transformer efficiency should reach 20% -45% of the rated
Voltage Reflection Now, most computer Power supply The rating is 100-240 volts, so they do not care about the input voltage is 120 volts, 208 volts or 230 volts. Similarly, they do not care about the input frequency is 50Hz or 60Hz.
In the traditional American design, UPS supply downstream transformer 480 volts, transformers reduce the voltage to 208 volts, assigned to the computer equipment. A 30-amp, 208 volt, 3 pole, 4-wire branch circuits can provide about 8kW load.
400Y230 volt distribution in the world outside the United States is the standard in many areas. Computer equipment power at 230 volts (line to the midpoint of the voltage). A 30 amps, 400Y230 volt, 3 pole, 4-wire branch circuits can provide about 15kW of load, is about the traditional 208Y120 volt system can provide twice as much. Therefore, practices in the United States, few downstream UPS transformers, were 1.5% -3% efficiency.
