When I was in college, I had this Job interview at an electric
utility company. The guy who interviewed me had the personality
of a turnip.
Like, no personality at all. Zero.
My eyes grew heavy. His voice started getting far away.
I began to slip into dreamland. I nearly fell asleep, just
listening to him describe the wonderful department he worked
in.
You never want to fall asleep in a job interview.
Late that night, I lay awake pondering... what could cause
this man to be so monotone, so featureless, so completely...
blah?
Suddenly it hit me: This man listens to 60 Hz transformers
humming day and night. 'Round the clock, 24/7. It's his
job to keep that sixty cycles per second going, 365 days
a year, without fail, so that our toasters and microwave
ovens keep toasting toast and popping popcorn. So that our
Tivos faithfully record episodes of Three's Company while
we're watching Seinfeld reruns.
Indeed, this 60Hz AC power is the very bedrock of civilization
itself. Should that power ever fail, we'll be plunged into
the dark ages again, with chaos, bedlam, looting and riots.
And if the 60Hz hum ever stops, it's HIS neck on the guillotine
blade.
Well, I didn't take that job. I took this job instead.
Designing these networking gizmos and what not here at B&B
Electronics.
So the other day we got this call. It's a guy named Matt
from a power utility. Matt is another one of the loyal servants
of mankind who keep the transformers humming.
Matt wanted to talk about his substations.
Matt liked his 60Hz but what he was not too enamored with
was the 1200 Baud. That's the speed at which the substations'
RTU communicated with the computer system in the Mother
Ship.
Plus, Matt's crew was making 2-3 trips a week to the substations
to reprogram breaker settings and retrieve history logs
- sometimes in blizzard conditions. Semis might be jackknifed
on the highway. Lovers might be separated. But Matt had
a duty to mankind which his team never failed to fulfill.
You probably don't know that most of those big high-tension
power lines have fiber optic cables on 'em? The substation
has two Single Mode Fiber Optic Cables coming in from headquarters.
Matt replaced the expensive RTU and 1200 baud with a high
speed LAN and a simple terminal server box. Not only does
he get the usual monitoring of voltages, currents, breaker
status, power usage, transformer temperature, etc., but
he can reprogram devices and bring back history reports
that the original SCADA system didn't support.
He doesn't have to make these trips anymore. Semis may
be jackknifed on the highway and lovers may be separated,
but engineers can reprogram devices and retrieve data from
their offices. Reports show millisecond by millisecond data
during fault conditions, and an Automated Meter Reading
System collects data for the billing computer.
The magic is achieved with a surprisingly simple array
of DIN Rail mount devices from our catalog:
- An industrial-grade Fiber to Copper converter puts the
data on the ever-familiar Blue Ethernet cable.
http://www.bb-elec.com/product.asp?sku=IMC-101-M-SC&s=072304
- A series of 5- and 8- port Industrial Ethernet switches
distribute the data throughout the substation.
http://www.bb-elec.com/product.asp?sku=EDS-405&s=072304
and
http://www.bb-elec.com/product.asp?sku=EDS-308&s=072304
- A 16-Port Serial Server converts Ethernet to RS-422/485,
extending Intranet access to all the serial devices
http://www.bb-elec.com/product.asp?sku=NPORT%205630-16&s=072304
- An RS-232 to RS-485 converter allows multi-drop communication
to SCADA devices with RS-485 ports:
http://www.bb-elec.com/product.asp?sku=485LDRC9&s=072304
- Some serial devices here are optical, to reduce electrical
noise; this converter links the fibers to standard RS-232:
http://www.bb-elec.com/product.asp?sku=FOSTCDR&s=072304
- For some devices, we need up to 2,000 volts of isolation.
This device provides that:
http://www.bb-elec.com/product.asp?sku=232OPDR&s=072304
My newfound curiosity about power distribution led me to
call Dave, an old college buddy who chose Power as his field.
Dave always gets a bit miffed when I poke fun at his life
where the definition of high frequency is 61 Hz and low
frequency is 59.
So I said to Dave: "So really, this power distribution
stuff isn't really as boring as it sounds - you guys actually
do some pretty cool networking and data acquisition tricks,
huh?"
Dave sez to me, "This stuff IS interesting. But Mike,"
he says, an alienated man yearning to be understood, "The
60Hz transformer hum IS interesting too."
Huh?
Trying to be open minded, I asked him to explain.
"You make it sound so...one dimensional, and it's
just not that way. There's 4160 volts... there's 13,800
volts, 35,000 volts, 115,000 volts and even 345,000 volts.
"There's not one phase, there's three. There's phase
to phase, and phase to ground. I'm telling you, transformer
hums come in all shapes and sizes.
"And it's not even confined to 60Hz. All those transformers
have half-wave rectification effects and hysteresis, which
makes an infinite series of harmonics - 120 Hz, 180 Hz,
240, 300, 360 - a Fourier series. Inside those humming transformers
is a complex world of voltages, harmonics, and deadly chemicals."
He sure showed me. I just wish the guy had explained all
this at my job interview. Had I understood this, I would
never have accused him of having the personality of a turnip.
I am now enlightened.
So... Let it be known that here at B&B Electronics,
we think ALL of our customers are exciting. Yes - even the
guys who keep the transformers humming.
Happy connections,
Mike Fahrion, B&B Electronics
Rants? Raves? Psychotic angles on Transformer Hum? Email
me: mailto:support@bb-elec.com
