Early Power Transmission
1917 - Transmission Line between Power Plant No. 1 and Los Angeles
The San Francisquito Power Plant No. 1 was placed in service in 1917 and energy was delivered to Los Angeles over a newly constructed 115 kV transmission line. The new lines ran the from Power Plant No. 1 to the Olive Switching Station and then to the Central Receiving Station in the city (now Receiving Station A).
The Los Angeles Bureau of Power and Light sold its excess San Francisquito generated power to Pasadena over two newly constructed 34 kV lines between the two cities.
115 kV transmission tower standing in front of Power Plant No. 1
|Power Plant #1 (1928)*|
The Olive Switching Station was constructed between 1916 and 1917 at the mid-point of the 115 kilovolt (kV) transmission line from San Francisquito Power Plant No. 1 to the central receiving station in the city (now Receiving Station A).**
The Olive Switching Station is the oldest such facility of the LA Department of Water and Power. It was a key element of the initial power development along the route of the Los Angeles Aqueduct. The station ensured the reliability of the system by allowing a section of any circuit on which trouble developed to be cut out without affecting service. The station remains vital to the operation of the San Francisquito Power Plants No. 1 and No. 2 as well as the facilities that bring water from the Owens Valley and Mono Basins to Los Angeles.
Early Transmission Line Construction
View of a single electric power transmission tower and line located in a scrub and low hill area. A single car sits directly under the tower. *
Construction of the Boulder Dam-LA Transmission Line
(1933)* - Scattergood 'Brings Home the Bacon'
In 1933 Ezra Scattergood travelled to Washington to borrow money for the construction of the Boulder Dam-LA Transmission Line. He was successful in obtaining a 10-year federal loan for $22,799,000. This enabled The Bureau of Power and Light to construct the historic 266 mile transmission line that brought Boulder Dam power to Los Angeles.
(One year later, LA voters approved a bond measure to refinance the original 10-year loan to a 40-year loan.)
|New Transmission Tower Design for the Boulder Dam-LA Transmission Line (1935)^^|
The Boulder-LA Transmission lines were constructed by the Bureau of Power and Light between 1933 and 1936. The lines consisted of two rows of towers 109-feet high and spaced 800 to 1,000 feet apart, at the time the largest in the world. They were built to carry 287,000-volt conductors a distance of 226 miles from the Boulder power plant to El Cajon Pass. From there, single towers 144-feet in height carried the circuits the remaining 40-miles to Los Angeles.^
|Click HERE for the Boulder Dam-LA Transmission Line Engineering Paper by E. F. Scattergood, presented to the American Institute of Electrical Engineers in 1935.|
Section of the 275,000 volt conductor used on Boulder line - Boulder Power Transmission System
|(1933)* - First squad of transmission line workers leaving from Power Bureau offices at 218 South Hill Street, June, 1933. At the peak of activity, more than 1,600 men were employed on the 266-mile project.|
LADWP Historic Archive
Early in June, 1933, the first fleet of trucks carrying men and materials got under way, headed for the desert area north of San Bernardino where the first Boulder transmission line construction camp was to be erected. Braving the desert’s scorching heat, these intrepid workers immediately set to work erecting portable shelters and drilling water wells in preparation for hundreds of other employees who soon would follow.
Camps were built at Boulder City, Jean, Kingston Valley, Silver Lake, Harvard, Victorville and Cozy Dell, each location in the approximate center of the single circuit construction section of the same name. The camps had sleeping accommodations for 150 men and kitchen and dining room facilities for 200. Each one was virtually a small town with its own water supply, electric lighting system, hospital, bath houses, butane gas heating system, warehouse and repair shops. At the peak of activities, about 1,600 men were employed on the project.
Road building was another important preliminary to actual line construction work, 270 miles being laid out over desert stretches, where gravel ballasting was necessary, and mountain passes, where roads in many spots had to be blasted out of solid rock. All construction material was hauled over these roads which now ill be used for patrolling.
In erecting the 2,695 steel towers a regular routine was followed. First the four footing excavations were dug, in most instances by an earth boring machine. In some mountain sections the footings had to be excavated by hand from solid rock. Tower stubs then were placed in the footings in a bed of reinforced concrete.
Tower erection was handled by three separate gangs. First was the assembly gang which assembled the steel parts into pre-determined units. Next came the erectors who erected the tower and installed all bolts. They were followed by the checking gang which checked all tower parts, tightened bolts and installed locknuts and turned in a final erection report.
Weights varied from 9 ½ tons for the standard single circuit tower to 13 tons for the standard double circuit tower. Angle and deadened types were considerably heavier. Many of the single circuit towers were erected in from four to five hours; double circuit towers in about 10 hours.
Approximately 1,600 miles of 1.4-inch diameter hollow copper conductor were strung, many special devices being designed by Power Bureau engineers to facilitate the work and prevent the cable from being scratched or kinked. Two steel ground wires were strung along the tips of each tower. These were connected through the tower steel to lines of counterpoise buried on each side of the tower line and connected by cross ties. This wire was placed by a counterpoise plow, also designed by Bureau engineers, which automatically dug the trench and laid the wire.
All clerical work was cleared through the field headquarters at Yermo where offices for the general construction and division superintendents and chief clerks were located.*^
|One method used in making emergency splices on the boulder transmission line cable. Photo shows duralumin? car in which patrolmen are lifted to work on cables (Date unknown)*|
|Boulder transmission line patrolmen fastening balance weight to second section of a special clamp used in connecting loose ends of broken cable (Date unknown).*|
|(December 1934)* - Transmission line crew keeping warm at lunch time at the base of a tower about 8 miles east of Jean camp on the Boulder Dam transmission line project.|
|(1935)* - Construction scene during erection of first double-circuit Boulder Canyon transmission line tower. A total of 257 towers of this type will be assembled in the final 40 mile link of the 270 mile power line from Boulder Dam to Los Angeles|
|(October 1935)* - Department of Water and Power workman joining sections of the last single-circuit Boulder Canyon transmission line tower in the vicinity of Mountain Avenue, near Claremont.|
|(1935)* - Last section of the first 144 foot high, double-circuit Boulder Canyon transmission line tower is shown being lifted into place. Tower is located in vicinity of Mountain Avenue, near Claremont, and is one of 257 double-circuit towers that will be erected on final 40 mile section of the Boulder Canyon transmission line|
|(1935)* - Double-circuit tower on the Boulder line|
|(1930s)* - Boulder power line test crew.|
Transmission Line Equipment and Methods
|(n.d.)* - The heavy duty truck above is being tested for use by the operating division for tower line construction. Bureau of Power and Light.|
|(June 1932)* - Insulator washing truck. Caption reads: 'Fires along the right of way of the Department’s 110,000 volt transmission line and the former difficult, awkward process of cleaning dirty insulators on high tension lines now can be handled effectively through the acquisition by the Transportation Division of a combined tank truck and extension tower'.|
Underground Transmission Lines
The DWP is noted for many "firsts" in the electric utility industry. In 1921 the Power System installed the nation's first 33,000-volt underground line.
Between 1962 and 1968 five 230,000-volt copper cable underground transmission lines were installed. They were the first lines of such high voltage to be placed in the local underground system.
In 1969, the highest voltage aluminum cable ever to be used in an underground installation was installed along a five-mile route between the Toluca Receiving Station and the Van Nuys Receiving Station.*^
|(February 27, 1969)* - Laying aluminum underground high voltage cable.|
|(1969)* - Jesse R. Easterling, engineering associate in Underground Transmission Design, closely feeding of aluminum 230 kv pipe-type transmission cable as he coordinates effort via walkie talkie with pulling crew 2,000 feet away.|
* * * * *
References and Credits