IEEE Power & Energy Magazine - March/April 2022 - 64

Joseph J. Cunningham
AC network centennial
years of distribution networks
A
64
AUTOMATIC AC SECONDARY DIStribution
networks are the norm in urban
areas of dense load concentration;
no electrical distribution engineer could
imagine any other technique. A century
ago, dc distribution predominated in
such urban areas. Alternating current
distribution was minimal, with radial
feeders from transformer substations
to the local transformers that supplied
customers. It was not as efficient or reliable
as dc and lacked battery backup.
Direct current distribution systems were
expensive, and ac promised a potential
500% reduction in distribution costs by
elimination of the substations and heavy
cables required by dc systems if reliability
and efficiency could be improved.
On 12 April 1922, a new ac distribution
method was proven on Manhattan's
Upper West Side, which determined
the future of urban distribution
and remains its backbone today.
On that day, the United Electric Light
and Power Company initiated operation
of the first fully successful automatic
distribution network in an area
that was pr imar i ly
residential with some
commercial customers-mostly
stores.
The United Company
had pursued ac
distribution prior to acquisition
by the Westinghouse
Electric and
Manufacturing Company
In this issue's " History " column, we highlight the 100th anniversary of a significant
milestone in distribution system evolution. On 12 April 1922, a new ac distribution
method was proven on Manhattan's (New York, United States) Upper West Side
that determined the future of urban distribution and remains its backbone today.
On that day, the United Electric Light and Power Company initiated operation of
the first fully successful automatic distribution network in an area that was primarily
residential with some commercial customers-mostly stores.
Joseph J. Cunningham returns for his 10th time to the pages of this " History "
column. Joseph has contributed to these pages on topics such as industrial electrification,
electric utility power systems, and electric rail transportation. His book
New York Power, was published in 2013 by IEEE History Center Press. We welcome
back Joseph as our " History " author for this issue of IEEE Power & Energy Magazine.
John Paserba,
Associate Editor, " History "
A century ago,
dc distribution
predominated
in such
urban areas.
Digital Object Identifier 10.1109/MPE.2021.3134345
Date of current version: 21 February 2022
ieee power & energy magazine
in 1889. The ultimate goal was a refined
ac distribution system superior
to that of dc. To that end, United,
in 1892, was the first utility to attempt
interconnection of supply transformers,
as noted in a 1936 paper by two Consolidated
Edison Company engineers,
Henry J. Sexton and Howard S. Orcutt.
Their work appears to
be the first historical account
of the process by
which urban ac distribution
developed.
Thirty Years
of Effort
That initial 1892 experiment
on West Street in
Lower Manhattan was
conducted by Station Master W. J.
Kelly, Superintendent Schuller, and
1540-7977/22©2022IEEE
Assistant Superintendent John T. Simon.
It connected two transformer
secondar ies, both supplied from the
same primary feeder from United's
Station K on Washington Street. The
system was overhead, with pole-mounted
transformers for lighting circuits. It
is considered the first use of banked
transformers (grouped in parallel with
secondaries tied together), and the concept
became the first single-feeder ac
system installed when the lines were
placed underground.
Little is known about the United
systems prior to 1896. Most evolved
from arc-light systems powered by
small, localized generating plants. The
West Street experiment displayed the
boldness of the company at a time when
most ac system components were still
experimental. The established Edison
march/april 2022
history

IEEE Power & Energy Magazine - March/April 2022

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