What power load does a DCS system require to have a 380VAC input?
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I would like to ask everyone: at what load level on the DCS system is it necessary to consider using a UPS with a 380VAC input to provide a 380VAC output? Also, is it easy to address the issue of three-phase balance for the 380V power supply? Thank you
We have used UPS units with a 380VAC input that provide a 220VAC output, as the DCS system requires only 220VAC; this approach is suitable in such cases, and there is no need to consider three-phase balance
Personally, I think your approach is feasible, but our design institute believes it is more reasonable to have 380V supplied to the UPS and then have 380VAC outputted, so that the cables don’t need to be particularly thick. Is there any standard specifying what level of load requires a 380VAC output?
There are no such standards; it has to be determined based on specific circumstances. If the UPS output is also AC380V, then the issue of three-phase balance must be taken into account. It’s a bit complicated, but it’s reasonable, especially when the UPS has a large capacity. However, if a hot-spare UPS is used, it is better to have a single-phase output.
Haven’t heard of it. They are all 220VAC; there is no 380VAC.
The price of units with three-phase input and three-phase output is also higher than those with single-phase output, so they are generally not recommended. If three-phase balance is indeed necessary, I would suggest connecting the power supply for each controller to one phase, connecting the operation station to another phase, and using the third phase as a power source for other auxiliary cabinets. Shenzhen Keda offers UPS units with three-phase hot standby functionality; we have used them and they work well
I would like to ask the experts: According to the specifications for UPS systems, it is recommended to use a single-phase output when the power supply capacity is less than 40 KVA； For capacities above 40KVA, a three-phase output is recommended, and the UPS must be capable of operating properly even when there is a 100% imbalance in the load across the phases over short periods of time. How should this passage be understood?