~1.5 GPM and then with only 50 percent
accuracy. Not until flow reaches ~5 GPM
does a turbine meter actually register
flow at an accurate level.
Verification Studies
If a water audit indicates a high
amount of nonrevenue water, a leak de-tection
study should be conducted, cou-pled
with an aggressive meter testing and
typing program. Testing should be priori-tized
using the utility’s billing and meter
database; the leak detection survey should
use acoustic methods or other appropriate
technology to quantify the amount of real
losses occurring simultaneously. A desk-top
review of individual account usage
with a turbine meter can be conducted to
estimate how many meters might be over-sized
or inappropriately typed. This two-prong
approach can further quantify the
audit, the relative distribution of real and
apparent losses can be determined with
a higher degree of accuracy, and overall
economic impact can be estimated. Relat-ed
savings may be used to justify the in-creased
analytics and labor saved through
installation of new meters and meter read-ing
technology.
Manual/AMR vs. AMI
In the late 1990s, new radios were
developed that accommodated “drive-by”
automatic meter reading (AMR),
and more recent advanced meter reading
infrastructure (AMI) provides even
greater efficiencies. When evaluating an
AMI fixed-based system and an AMR
drive-by system, utilities should perform
an AMI/AMR feasibility study to
consider potential benefits of leveraging
related analytics for improving overall
efficiencies.
34 SOURCE fall 2017
System reliability and data storage
capability will vary by vendor. A typical
AMR system will include a new meter
transceiver unit/meter interface unit
(MXU/MIU), which will typically store
from one week to over one month of data
depending upon compression settings
and technology. Data resolution can also
impact storage capabilities. A register
configured to read down to 1/10 of a cu-bic
foot could result in less data storage,
whereas lower resolution will often re-sult
in longer storage intervals although
sacrificing analytical capabilities. Instal-lations
with an industry standard meter
register can usually store over 40 days of
data with one-hour data resolution. For
AMI systems using a typical collector,
storage times usually will increase well
beyond 30 days. Longer intervals of data
that can be subject to real-time auditing,
and analytics can be realized using the
related AMI database server where the
vendor provided data storage is typical-ly
up to two years or more.
Database reliability is important and
utilities must consider potential down-time
associated with loss of power to the
collector. Solar power is subject to local
weather conditions, and collectors on
grid power are subject to utility power re-liability.
Battery backup for the collectors
is typically sized for a minimum of three
days of backup power.
Radio reading technology using
drive-by or fixed base AMI in the 450 or
900 MHz frequency ranges will generally
provide the lower long-term cost solution
for systems with a large number of end-points
to read and communicate with on
a regular basis. Cellular communications,
on the other hand, can reduce initial cap-ital
costs and provide a viable solution
to fill coverage gaps in service territories
with a mix of urban, suburban, and rural
geographies. S
Table 1. AMR vs. AMI Benefits Comparison
If a water audit indicates
a high amount of
nonrevenue water, a leak
detection study should
be conducted, coupled
with an aggressive
meter testing and
typing program.