Commercial AC power outage - restore Voltage ?

[Chip Fetrow]

Well, no.

When the power company, whatever company it is, restores power, it is a result of slamming the switches closed, and there is no way to ramp up the Voltage or gently do anything.  Zero crossings do not matter.  Just close the contractor or switch.

They DO tend to bring up smaller areas because of in-rush currents.  I have discussed this at length with power companies.  The two main ones were SMECO and Virginia Power.  I have also worked with PEPCO, but -- and this may be hard to accept -- they really didn't seem to care much.

VEPCO paid attention to me after a while.  They understood what when I told them my 208 Volt feed was at 250 VAC, I actually knew what I was talking about.  It was pretty funny to see a bucket truck show up on a 25 MPH street at about 50 MPH and squeal to a stop.  They went to the transformer and freaked out.  It didn't matter to me because I pulled the main breaker and went to generator.  Most of the two-way and paging customers were off the air, but better that than frying radios.

SMECO was MUCH easier.  They wanted my station to announce their "issues" on the air, and if they didn't treat us properly, we might not.  Of course, we would, but  better they didn't know that …

SMECO generates only peak shedding power, but it happens to be a lot, mostly gas turbine.  Imagine that!  An area with one of the biggest nuclear pants in the area doesn't have base feed.  The power from Calvert Cliffs goes to BG&E, and BG&E then sells power to SMECO.

SMECO had a huge power outage in the early 90s.  We (WXTR) were on our diesel generator for 17 days.  I was BEGGING SMECO for restoration.  They said no, because we had a generator.  They told me that if our generator failed, they would increase our response time.

We burned about 9 gallons an hour.  We had a 50 gallon tank.  Um, bad.  A contract engineer and I ran around from Wal-Mart to Wal-Mart and hardware stores buying gas cans.  At one Wal-Mart they couldn't take credit cards because the sat dish on the roof was iced up.  We offered to fix it.  They declined.

We would go out and get about 40 gallons of road taxed diesel and kept the station on the air.  It took two trips a day (though one would have worked).

I was sitting in my dark office, listening to the radio, my radio station, and the announcer told the public that SMECO had returned power to the entire area.  I went into the studio and the power failure light was still lit on the remote control.

I called SMECO and they told me - whoops, sorry.  Within about 45 minutes we had our power back, and I allowed our vendor to fill the fuel tank.

In dealing with power companies I have found they can only close switches.  No zero crossing concerns.  No ramp up.

They see inductance bumps.  They don't really care.  It is OUR problem.

To answer your question in short, don't trust the power company.  Get a bunch of UPSs to protect your equipment -- or let it fry.

--chip

On Aug 22, 2013, at 1:00 PM, tacos-request at amrad.org wrote:

> Message: 1
> Date: Wed, 21 Aug 2013 23:56:51 -0400
> From: 3t3 <3t3 at comcast.net>
> To: AMRAD reflector <tacos at amrad.org>
> Subject: Commercial AC power outage - restore Voltage ?
> 
> Hello -
> 
> When the electrical power companies restore electrical power to a 
> neighborhood after a widespread power outage, what initial "start up" 
> voltage do they send out on the line to accommodate the instantaneously 
> huge start up current surge needed to get "back on the air" in a 
> "stable" condition ?
> 
>     Terry McCarty
>    3t3 at comcast.net
>        wa5nti