[time-nuts] Yukon Energy causes time sync problems
bill at iaxs.net
Sun Apr 11 00:20:13 UTC 2010
Still having fun with this.
Looked up Yukon Energy, expecting to find something in Alaska. Wrong.
The company is in Yukon Territory, Canada (On, you huskies ...). It
has three hydro plants that generate 75 megawatts for 1700 customers.
It sells some of that power to Yukon Electric, which implies tie lines
but may be DC.
They have 39 megawatts of diesel generators on standby, perhaps for
when the river freezes up, or a log gets into a turbine.
Although the picture in the article shows computer monitors, the story
says that their reference clock is not digital:
"Morgan said staff at the control centre synchronize the time between
a sophisticated but regular electric wall clock fed by a dead-accurate
satellite signal as a means of keeping power generation in check."
I guess "dead-accurate" is close enough for power company work, surely
better than "dead wrong."
"Regular wall clock" implies a synchronous clock, possibly a twin to
the clock connected to the local generator bus. But maybe it just looks
like a regular clock, and runs on 100 Hz. I can tell you that the 1 KHz
clock in the HP-113 sang so loudly it would drive you from the room.
In my youth, I took electric clocks apart to see what made them hum.
There was always a gear train between the motor and the hands, with
no possibility of anything slipping. Unless, that is, the thing is so
old that the holes in the brass plates that hold the gear shafts have
worn enough to let gear teeth slip.
The other thing that can slow a synchronous clock is that the oil in
the gear case attached to the motor has turned to tar. Old clocks could
sometimes be saved by carefully drilling a small hole (don't get chips
inside) and injecting a bit of solvent. The motor is so heavily loaded
that it slips out of synch and runs as a shaded pole induction motor,
at less than synchronous speed.
Seeking precision time can indeed take some strange directions.
Don't understand the reference to huskies? Google "Challenge of the
Yukon" or "Sergeant Preston"
From: Brooke Clarke
Sent: Thursday, April 08, 2010 12:58 PM
To: Discussion of precise time and frequency measurement
Subject: [time-nuts] Yukon Energy causes time sync problems
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