To be more precise, each HV transformer is capable of 2560 EU/t.
You can power 20 electrolyzers per, so have four HV transformers with all five sides connected to a single point, then you can connect each of the four combined points together into a single line to power all your electrolyzers. Transformers aren't expensive so I'm not going to optimize your solution for materials, it'll be better for modulation anyways. This way you can turn off your centrifuges or electrolyzers separately.
288 centrifuges at 5 EU/t (I assume, I don't know, adjust the calculations accordingly if not) is 1440 EU/t. That means ONE HV transformer is capable of filling those needs. Though, remember that you have to down step your power.
Each MV transformer is capable of outputting 128x5 EU/t, or 640 EU/t. Each LV transformer is capable of outputting 32x5 EU/t, or 160 EU/t. This means for every 640/5 = 128 centrifuges you'll need an extra module consisting of one MV transformer with all five sides connected to one point, then that power outputted to 4 LV transformers, with the same set up.
In summary, you will need 5 HV transformers as a control for the power. Your electrolyzer set up will require 64/5 MV transformers or about 13 of them. Make sure you have one face for each electrolyzer connected to the line. (i.e. You will need to have all 5 faces of each MV except for the last one, connected to the line supplying the energy to the electrolyzers.)
The subsequent modules will consist of 128 centrifuges, 1 MV transformer (all five sides) and 4 LV transformers. You will need at least three of these modules. The last one will have 288 - 128x2 = 32 centrifuges only. If you want to optimize the set up so you waste less, I'll leave that to you. I'm tired.