Sent from my batphone

> On Mar 25, 2017, at 11:54 AM, (via tml list) <xxxxxx@simplelists.com> wrote:
>
>> On 25 Mar 2017 at 0:36, Alex Goodwin wrote:
>>
>> GT: Starports gave me the impression that (at least) Imperial
>> starports make a point of both being able to generate their own power,
>> independent of local grid (assuming there IS one), and being able,
>> subject to director's discretion, to black start same
>
> More stories from the Great Blackout.
>
>
> So being required to have backup power or the ability to cold start
> just means that gear is installed. Doesn't mean that it'll actually
> *work* when the real thing comes along. Not even if it has been
> tested.
>
> Usually it's a *real* mess trying to *realistically* test emergency
> power. You can make sure the generator runs, but unless you actually
> cut the main power completely, and without warning, you can't *know*
> that everything will work.
>

I used to work in an environment where the power systems were rather important - we were "allowed" 5 min of planned downtime a year.

We had batteries in each equipment rack with 1 hr run time each. A room based battery for the datacenter with 2 hours runtime. A hydrogen fuel cell which could run the facility for 2 months. A diesel generator with 2 weeks fuel. And connections to two separate power grids.

We tested it monthly.

First we would cut utility power, and wait for the generator to cut in - that took a few minutes and tested the batteries. Then we would shut down the generator and the fuel cell would take over.

It was fun to watch the first few times - but then it became pretty routine. :)