Publication: Electrical Doings
New York, NY, United States
THE LONGEST ELECTRICAL
IN THE WORLD.
The most notable power transmission plant yet attempted, both from the point of view of amount of power and the distance of transmission, is already under way in the State of Utah.
The Pioneer Electric Power Company, of Ogden, Utah, has within the past month placed a contract with the General Electric Company for a complete 5,000 horse-power, three-phase plant, covering a transmission of thirty-six miles from Ogden to Salt Lake City.
The power will be obtained from the fall in the canon of the Ogden river, at a point almost within the limits of the city of Ogden. Across the head of the Ogden canon a dam is to be thrown, and an immense storage reservoir formed, which will cover some fifteen or twenty square miles of a valley in the mountains. From this dam to the power house is a distance of nearly six miles. The water will be carried through a six-foot pipe of wood for about five miles, while for the rest of the way it will pass through a six-foot pipe of rivetted steel. These pipes are fitted at intervals with automatic relief and air valves to prevent the bursting or collapsing when the flow of water is varied by changes of load. The effective head of water at the power house will vary from 400 to 450 feet and the full capacity of the pipe line will be 10,000 horse-power.
Two duplicate receivers will be used, one at each side of the power house, so that either can be shut down without stopping the plant. To these pipes running to the water wheel nozzles will be connected. The speed of the wheels will be controlled by Knight governors and the valves will be operated by hydraulic pistons so that the generators may be stopped and started from the switchboard. The water from the wheels on each side of the power house will pass into a central tail race under the floor between the two lines of generators and will be conveyed into canals for the irrigation of some 18,000 acres of land in the vicinity of Ogden, which will be reclaimed for farming purposes.
The electric plant at first will consist of five 1,000 horse power twenty-four pole three-phase generators driven by Knight water wheels running at 300 revolutions per minute. The water wheels and fitting will be furnished by the Risdon Iron and Locomotive Works, of San Francisco. Water wheel and armature are mounted on the same shaft, and are supported by the same base frame and bearings. The periodicity of the current is sixty cycles per second and the generators will be wound for 2,300 volts.
Two exciters, each of 100 kilowatt capacity, direct connected to their own water wheels, will be provided, either of which will suffice to excite the fields of all the generators in the completed station.
The current from the generators will be carried by load covered cables laid in ducts between the generator foundations and the wall of the building to the generator switch-boards at one end of the power house. The boards will be blue Vermont marble panels and will be completely equipped with all the necessary controlling and regulating instruments and apparatus. Tachometers on the switchboard, operated by synchronous motors electrically connected to the generators, will indicate the speed of the machines.
The step up transformers and the 2,000 and 15,000 volt feeder panels will be placed in a gallery erected over the generator switchboard. The transformers, nine in number, each of 250 kilowatt capacity, will raise the generator potential from 2,300 volts to 15,000 volts, at which pressure 2,000 horse-power will be transmitted to Salt Lake City. The local distribution of the balance at Ogden will be made at 2,300 volts.
The transmitted current will pass over six No. 1 wires strung on insulators of a special porcelain developed by the General Electric Company, to withstand high potentials to nine 250 kilowatt step down transformers at Salt Lake City, which will deliver it at 2,300 volts for distribution.
The transmission line and transformers will be arranged to allow of the use of a potential of 25,000 volts. This will permit of the efficient transmission of current to the mining regions of Mercur and other camps thirty to thirty-five miles beyond Salt Lake City. All lines will be protected by the latest types of General Electric Lighting Arresters, which have proved so efficient in other transmissions.
To construct the iron and wooden pipe bringing the water to the wheels 100 horse-power in motors are set up in the shops of Rhodes Bros. in Ogden, supplying extra power for the work, which is one of the most extensive pipe line contracts ever undertaken — five miles of six-foot wooden stave pipe, and one mile of six-foot rivetted steel pipe. Practically all the work will be done on the ground, the steel being received in flat sheets to be rolled, punched and rivetted in the shops and the lumber for the wooden pipe in the rough to be milled, planed and put together on the spot.
Salt Lake City, with the completion of the Pioneer plant, will receive power from two of the most important electrical transmission installations ever undertaken. That transmitting the power from the Big Cottonwood canon has only recently been completed, that of the Pioneer Company will probably be inaugurated about the first of November of this year.