How we keep power on when the grid drops

01Power

Start with two feeds

Our site takes power from two 33 kV feeds that come from separate substations on different routes. When a storm brings down a line on one side of Enugu, the other feed usually keeps going, and the building does not even start a generator.

Two feeds cost more to bring in. We paid it once so that our customers do not pay for it in outages every rainy season.

02Power

Generators that start themselves

When both feeds fail, switchgear watches the voltage and signals the generators to start. Within ten seconds they are carrying the load. Nobody has to find a key or wake a driver.

We run four 1,250 kVA sets in a 2N layout. Any two can carry the building, so one can be in service and another can fail on the same day without trouble.

03Power

Fuel is a supply chain, not a tank

A generator without diesel is a very heavy box. We keep 72 hours of fuel on site, test it for water and bugs every week, and hold contracts with two suppliers who deliver from different depots.

Two of our sets also run on piped gas, which gives us a third source when roads are closed or diesel is short.

04Power

The UPS fills the gap

Ten seconds is too long for a server. Double-conversion UPS units carry the load from the moment the grid wobbles until the generators are ready, and filter the power the rest of the time.

Each rack gets two strips from two separate UPS systems. If one UPS is out for battery work, the other carries the rack.

05Power

Test it until it is boring

Every Tuesday a generator runs on load for an hour. Every quarter we switch off a utility feed on purpose and watch everything transfer. Boring tests are how we avoid exciting nights.