CITY OF LAKE WORTH, FLORIDA
UTILITIES DEPARTMENT
A Look at our Electric
Utility
A Plan For The Future
THREE FACITS OF PLANNING
:
•SUPPLY - is being addressed through the
RFP process and is not included in this
effort
•TRANSMISSION - is included in the plan as
well as addressed through the RFP
process
•DISTRIBUTION – The main focus of our
presentation today. Commonly referred
to as poles and wires
Electric Utilities Long Range Plan
WHERE DID WE START?
• 40 sectors of service (or feeder as we engineers
like to call them) have been identified for the
Lake Worth Electric Utility territory
• Each of these sectors serves approximately 200
thousand watts (2MW) of power demand
• There are on average 650 customers per sector
Electric Utilities Long Range Plan
A LOOK FROM THE METER BACK TO THE SYSTEM:
• Most of our meters are ‘dumb’ devices - they read the current that flows
from the system to the house.
• Current technology allows meters to do much more.
• Smart meters can communicate with the customer’s house through
internet and ‘talk’ to smart appliances as well as control devices.
• They can also communicate with the utility by reading consumption,
diagnosing electric problems, or providing service such as ‘pre-pay.’
• Our long range plan includes development and implementation of a
communication backbone to support smart metering.
Electric Utilities Long Range Plan
OVERHEAD OR UNDERGROUND?
• Currently, the service wires that connect to the
customers’ houses are primarily overhead from rear lot
lines or alleys.
• The ultimate system would have all of these service
wires underground from a system in the front or street
side.
• This plan will implement a combination of both, with
all circuits East of Federal underground and a
combination of underground and overhead West of
Federal.
Electric Utilities Long Range Plan
• Deciding factors:
– Cost has in the past been a major factor. However,
cost differentials have diminished and in some
cases underground distribution systems can be as
cost effective as overhead systems.
– Reliability or storm issues are major consideration
for our coastal system.
– Other elements of nature associated with a coastal
construction, i.e. salt spray.
– Line location (street or alley) and line type
(distribution, transmission, or subtransmission)
must also be considered.
Electric Utilities Long Range Plan
SO WHAT DO WE HAVE?
• Differing types of construction and voltages 26kV distribution systems, 26kV subtransmission
systems, and 4kV distribution systems.
• Nine substations directly serving customer load.
• Two substations serve the transmission and
subtransmission system.
• Tree growth into overhead lines, animal contacts,
lightning, and material failure due to age.
• Limited ability to sectionalize or ‘switch’ the
system
Electric Utilities Long Range Plan
WHAT ARE OUR GOALS?
• Standardization of construction designs and materials.
• Standardization of substation protective devices
(breakers and relays).
• The ability to isolate and utilize adjacent ‘sectors’ to
switch the distribution system for increased
reliability.
Electric Utilities Long Range Plan
HOW DO WE GET THERE?
• Do we utilize existing voltages?
• Do we convert to a different distribution voltage?
• Do we build a new subtransmission system?
• There are NO WRONG answers.
Electric Utilities Long Range Plan
THE PLAN:
• We are proposing to keep all of the existing substations to
serve customer load
– The sites already exist and the infrastructure is in place.
– The ‘sectors’ are defined by these substations so we can utilize
existing systems to a great extent.
– Using multiple substations will minimize the customer exposure
to system problems.
– Using multiple substations will maximize the capability of the
system flexibility.
– Each substation will require less work (which translates to less
money) when upgraded.
– Using all existing substations will allow for a more systematic
rebuild/conversion process.
Electric Utilities Long Range Plan
• We are proposing a 26.4kV subtransmission system.
– A strong 26.4kV loop already exists throughout the service
territory.
– Most of the substations are built with 26.4kV equipment.
– A 26.4kV subtransmission system will effectively serve the
distribution system after reconfiguration.
– Conversion to a higher voltage subtransmission system can
be accomplished utilizing this same plan if load dictates
however, economics do not justify a subtransmission
conversion at this time or in the foreseeable future.
Electric Utilities Long Range Plan
• We are proposing a 13.2kV distribution system.
– 13.2kV is an industry standard voltage.
– Equipment and materials are readily available for this
voltage.
– Linemen are trained to safely work on a 13.2kV system.
– Coordination of system protective devices (breakers, fuses,
switches) is achievable.
– A 13.2kV distribution system will handle the Lake Worth
load for the foreseeable future in an efficient manner.
– A 13.2kV distribution system coupled with a 26.4kV Subtransmission system is the most economical approach to
manage system losses.
– voltage support will be strong and system flexibility will be
maximized.
Electric Utilities Long Range Plan
STAGES OF THE PLAN
• Stage 1 --- installation of backbone communications for
smart grid technology, system protection devices, and
system operations control and data acquisition (SCADA).
This stage is in planning and development and will ongoing
for the next 3 years.
• Stage 2 --- conversion of 4kV and 26.4kV distribution to
standard 13.2kV distribution; unloading the existing
distribution from the 26.4kV system. This stage will be
ongoing for 10 years in conjunction with Stage 3.
• Stage 3 --- development of a looped 26.4kV
subtransmission system and development of a secured
138kV transmission system. This stage will be ongoing for
10 years in conjunction with Stage 2.
Electric Utilities Long Range Plan
PREVIOUSLY COMPLETED:
• Eight 138kV transmission circuit breakers were
purchased; six were installed in 2009/2010
• Thirteen 26kV subtransmission circuit breakers
were purchased; 11 were installed in 2009/2010.
• The remaining 4 circuit breakers will be installed at
Main substation and Hypoluxo substation as
defined by the Plan.
Electric Utilities Long Range Plan
PLAN SPECIFICS:
Proposed costs include labor, transportation, material, and
equipment.
• Purchases include:
– Twelve 26.4-13.2kV substation transformers estimated
to be $375,000 each for a total cost of $4,500,000.
– Ten 26kV circuit breakers estimated to be $50,000 each
for a total cost of $500,000.
• Distribution system (stage 2) rebuilds to support the 40
sectors will cost an estimated $14,750,000 over the next 10.
• Total project cost over the 10 year period is $22,587,778.
Electric Utilities Long Range Plan
AGGRESSIVE TIMELINE APPROACH:
• A 5 year conversion plan can be implemented with 25% of the
system converted each year and the transmission and
subtransmission systems reconfigured in year 5.
•
– Pros: The system will be state-of-the-art in a short time frame
resulting in the best reliability. Parallel systems will be
operated for the shortest time frame. Underground systems will
replace overhead systems in designated areas resulting in
aesthetics and operating improvements.
– Cons: Costs will increase due to the need for contractors. Cash
flow will be required in a shorter time period. Customers will
need to accommodate the utility schedule rather than the utility
working with the customers for system improvements.
Electric Utilities Long Range Plan
CONSERVATIVE TIMELINE APPROACH
• A 10 year conversion plan will be implemented with 15% of the system
converted each year and the subtransmission system rebuilt in conjunction
with the distribution conversion. The transmission system will be
reconfigured in year 5 independent of the conversion project.
– Pros – The system will be rebuilt by in-house crews made up of existing
linemen and new apprentices allowing for a training period for the new work
force before attrition (retirements) takes the existing skilled work force
knowledge base away. The ‘smart grid’ technology will be better defined and
standards will be in place lessening the potential to invest in a system that may
become obsolete. Costs will be spread over an additional five years, relieving
the cash flow issue. Customers will have more time to work with the utility to
best implement a plan of service.
– Cons – The system will be operated at 3 voltage levels for a longer time frame.
The subtransmission system will be utilized as a distribution system for a
longer time period resulting in a potential reliability reduction.
Electric Utilities Long Range Plan
PERSONNEL
• Currently there are 3 line crews composed of 9
linemen, 1 substation crew composed of 2 linemen,
and 4 troublemen.
• It is proposed to develop a lineman apprenticeship
program and add 5 new line apprentices over the
next 5 years.
• After 5 years the attrition in the electric T&D
department will place the staffing back to the
current level.
Electric Utilities Long Range Plan
WHAT FACTORS DID WE CONSIDER?
• Information from four previous distribution system
studies.
• Existing voltages and services currently serving our
customers.
• Optimization of existing systems and the ability to
provide the best value in terms of initial cost, lifetime
costs, reliability, operational flexibility, and aesthetics.
• The need to provide detailed steps of initial
construction and conversion processes.
• The need for follow-up construction and system
operations.
Preparing to Serve our
Community for the next
100 years