[AusNOG] DC undervoltage issues

[Tony de Francesco]

joshua,

Undervoltage at the street mains supply to the DC would probably be the
result of excessive power draw on the main electrical grid.

However, if a double conversion static UPS system is used as the main DC
UPS, the A+B supply voltage should remain at a very stable 240V AC.

Many new UPS systems are designed for lower losses and deliver power
straight through with some minor voltage regulation  (known as line
intetactive UPS).

It could bd possible that the DCs main UPS is in bypass mode (due to a
fault or maintenance) in which case you would bd seeing the street voltage.

Another less likely possibility is that current draw within the DC is at a
peak and cresting excessive voltage drops.

Regards

Tony de Francesco
Technical Director
P.U.E. Pty Ltd
Mob: +61 (0) 457 701 179
Email: tonyd at pue.com.au
On 15/01/2014 10:15 PM, "Joshua D'Alton" <joshua at railgun.com.au> wrote:

> Evening noggers, hope you're all surviving the heat, especially in VIC!
>
> Speaking of, in 2 DCs were seeing borderline undervoltage on our UPSs (yes
> we run them even with A+B power because sensitive equipment), I've read
> that there are power issues in VIC at the moment, but I thought they were
> limited to residential zones (with rolling black/brownouts)?
>
> Anyone else seeing this, or have comments?
>
> As a side question, does anyone (perhaps Bevan?) know if DCs will manually
> switch to genny/backup power in this sort of scenario, if so details would
> be nice.
>
> (with regards to that, I looked at one DC contract and it doesn't mention
> anything about the specifics of power delivered, just that it is A+B with X
> battery backup and Y generator capacity, and Z SLA, doesn't mention what
> sorts of voltages would break said SLA...)
>
> Anyhoo, cheers!
>
> PS, also seeing strange intermittent issues with Telstra and Pacnet
> connecting to local google and others, not sure why the power quality would
> affect that, but..
>
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