Automated Meter Reading
In early 1998, FLEC began replacing manually read electric power meters with automated
devices called Turtles. Automated Meter Reading, or AMR, has a number of benefits.
For one, once fully deployed, AMR allows FLEC to eliminate the cost of sending an
employee out to locate and read every meter in the system. As a side benefit, the
system eliminates manual data entry into the billing system each month and reduces
the number of possible human errors in the billing process.
The system FLEC has chosen is called the Turtle system from Hunt Technologies, which
transmits meter readings over the actual power lines without the need for expensive
radios. Electric power meters are very simple devices conceptually. They are essentially
electric motors which turn at a speed proportional to the amount of power passing
through them. The motor speed is governed by the physical construction of the meter
and cannot be changed except for minor adjustments which can be made to correct
a meter that is aging and running too slow - they cannot be made to run too fast.
This motor is then connected to a series of gears which move the dials on the face
of the meter in an exact ratio such that the number of turns of the motor is converted
to a number of kilowatt-hours of energy usage. This counting and conversion calculation
is a fixed ratio and never varies, much as the gears in a watch always allot 60
seconds to each sweep of the minute hand, and 60 minutes to each hour. To implement
AMR with Turtles, a small electronic module is installed inside a standard power
meter - no other change is made. This module simply counts the number of turns of
the motor inside the meter and reports the number at regular intervals using a signal
transmitted via injected frequencies over the power line. This information is collected
by a receiver installed at a substation and held until requested by a computer at
the main office.