Questions regarding the 35/10KV substation
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If there are no 10kV electrical equipment in the factory, can a 35/0.4kV substation be installed directly to eliminate the need for an intermediate step of voltage transformation? The power supply company says that for factories with a capacity of over 20,000 kW, a 35/10 KV substation is necessary. Is this reasonable? Thank you
Select the appropriate voltage level based on the load; it is completely correct to choose a 35 kV voltage level for a 20,000 load. 20,000 – Transformers with a voltage of 35/0.4 kV are extremely large in size; it’s unlikely that any manufacturer produces them. It’s also not possible to use low-voltage power inputs, and the design is unreasonable; this option should not be considered.
10/0.4kV substation can be configured
I’m honest with you – there are manufacturers that produce them.
It’s really hard to say; each specific project needs to be analyzed individually. It’s impossible to give an answer just by mentioning a concept. I’ve really never seen a factory with a capacity of 20 MVA that doesn’t have any 10 kV electrical equipment. Is 35kV used for high voltage? 35/0.4kV transformers are available, but those with a capacity over 4MVA are generally not chosen due to the high low-voltage short-circuit current. For a 20MVA, 35/0.4kV transformer, it’s really hard to figure out how to choose the voltage level for the low-voltage side. If low-voltage equipment is indeed grouped by area, 35/0.4kV transformers for those areas can be used. To go deeper, it is necessary to conduct a comparison of various options and carry out an analysis of economic benefits.
35 kV transformers with a capacity of 20,000 units are quite common, but transformers with a low-voltage side of 0.4 kV and a capacity of 20,000 units have indeed never been seen. The current on the low-voltage side of the transformer is nearly 30,000 amperes; how large must the low-voltage windings of the transformer be? ? :o
In the areas where various loads are concentrated in locations with 10Kv transformers, the 10KV line losses are much lower than those of low-voltage systems (400V)! In this way, only one 10KV cable is needed to go from 35KV to the substation, thus solving the problem. We arrange it this way; of course, it needs to be considered in its entirety during the overall planning stage! ! !
Thank you, I understand. It’s not reasonable to do that.