Brownout in the UK - a doozy

[Palindr☻me]

A good one tonite.

Power went off for a few seconds and then came back on at between 175
-190 volts for nearly 3 hours. The farm next door lost two phases
completely, apparently had the same wandering and low voltage on the
third and now have two out of the three back with nothing on the third.
It is going to be fun come milking time if all three aren't back. He
will just have to ditch the lot.

Any thoughts what could do that to a distribution system? I have never
seen a brownout like that before, in the UK.

I ran off the inverter for a while and then started the genny. I am not
sure what I have around the place that wouldn't be happy running of that
voltage for that length of time but didn't really want to find out.
Still, I know all my UPSs work ok now.

 

[Phil Scott]

A good one tonite.

Power went off for a few seconds and then came back on at
between 175 -190 volts for nearly 3 hours. The farm next
door lost two phases completely, apparently had the same
wandering and low voltage on the third and now have two out
of the three back with nothing on the third. It is going to
be fun come milking time if all three aren't back. He will
just have to ditch the lot.

Any thoughts what could do that to a distribution system? I
have never seen a brownout like that before, in the UK.

I ran off the inverter for a while and then started the
genny. I am not sure what I have around the place that
wouldn't be happy running of that voltage for that length of
time but didn't really want to find out. Still, I know all
my UPSs work ok now.

dont run electric motors, refrigeration, pumps etc especially
3 phase on low voltage, you can easily burn them out that way.

Phil Scott

 

[daestrom]

A good one tonite.

Power went off for a few seconds and then came back on at between 175 -190
volts for nearly 3 hours. The farm next door lost two phases completely,
apparently had the same wandering and low voltage on the third and now
have two out of the three back with nothing on the third. It is going to
be fun come milking time if all three aren't back. He will just have to
ditch the lot.

Any thoughts what could do that to a distribution system? I have never
seen a brownout like that before, in the UK.

I ran off the inverter for a while and then started the genny. I am not
sure what I have around the place that wouldn't be happy running of that
voltage for that length of time but didn't really want to find out. Still,
I know all my UPSs work ok now.

Sounds like a fault in a substation. Probably a transformer. Often, three
single-phase transformers are connected together for supplying three phase
service. If something faults one, you get two hots and the third is dead.

As far as such low voltage, the most common suspect is when two or more
distribution transformers are tied to various parts of a line, and one goes
down, the remaining ones can't support the voltage over the entire length of
the line.

I'd have called the utility (in the US) and asked what they can do and how
long it will be. Don't try to run three-phase motors on single phase
though, they'll burn out.

daestrom