How do you maintain a constant power supply to a place 24/7 using a generator, commercial power, or solar?

Question

Hi, I'm Sadiq. I'm doing bachelor of science in telecommunication engineering. I was given the above mentioned question which was part of an academic research project, but unfortunately I was not able to get an answer for it, so I forwarded it.

Answer 1

In telecommunication it won't be as critical as in a hospital, for instance, but I have worked in the University Hospital of the University of Antwerp, Belgium, and it may be interesting to know what they have:

• 3 levels of criticality: a no-break circuit which should never be interrupted for more than a second, a second level which was allowed power interruptions of a few minutes, and non-critical. The no-break circuit was typically for operating rooms and intensive care. Second level for other patient care. Third for non-patient devices (think kitchens).

• Batteries. Solar is no good: Murphy's Law says that power-downs occur when there's the least alternative power available. The emergency generators needed a couple of minutes to get started, and the batteries (lots of them) should provide the energy to bridge that time for the no-break circuit. Once the generators supply power to the grid the second criticality level is connected again.

• Direct power lines to two different power plants. Even if the grid would go down both plants would decouple from it and keep supplying power to the hospital. And even with the grid and one of the power plants down the hospital would still get power from the other plant.

For a telecommunication application this is obviously overkill, but you'll have to decide whether you need the no-break circuit. And how much power do you need? Is this for a 10 kW transmitter? If you can live with a a short time of power-down you may not need the batteries to power the equipment, and then the generators will do. You'll need batteries to start the generators, and to keep your system controller powered though. The controller will have to switch the contactors once the generators run at the right frequency, so that they can power the equipment from that moment.