UPS main power supply and bypass power supply
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According to the HG_T20509-2014 Specifications for Instrument Power Supply Design, section 5.3.3 states that the UPS main power supply and the bypass power supply should preferably be powered by different busbars. What does this mean by different busbars, and how should I specify this requirement to the electrical engineering team?
The instrument power supply should be classified as a particularly important load among first-class loads; I consider the main power supply to be a first-class load. Can the bypass power supply be used as long as it is not in the same cabinet?
It shouldn’t be on the same external line
The BUS refers to the different bus segments in power distribution design; 5.3.3 states that the UPS main power supply and the bypass power supply should not be powered by the same bus segment. You can look at a schematic diagram to understand it.
I’m not quite sure. Is there any question here? It’s just necessary to provide two power supplies for the electrical system; the notes state clearly that they should come from different busbars. The standards are very clear on this
May I ask, is it sufficient to just mention the different bus sections, without specifying the load level?
I overlooked this; I checked the standards yesterday, mainly to determine the boundary between your team and the electrical department. Our UPS is under the responsibility of the instrumentation team, whereas according to standards, the design of the UPS should be handled by the electrical engineering team. The instrumentation team only needs to provide the electrical department with information regarding the number of UPS output circuits; by specifying your power consumption requirements, it is determined that the power used by the UPS constitutes a first-class load.
Here, it’s also the instrumentation department that is responsible for the design of UPS systems; the electrical department only provides power supply, and we put forward the requirements.
Are you sure it’s a first-class load? A first-class load requires not just different buses, but also supply from two separate power sources. In other words, if two different transformers are used to supply power, then the incoming lines for those two transformers must also be separate circuits.
Things like load levels and the number of electrical circuits have nothing to do with electrical engineering; you just need to specify the UPS capacity required as well as the requirements for the power supply connections
It’s sufficient to ensure that the electrical supply meets the requirements for first-class loads