Ogden, Utah power line with GE porcelain insulator

Long-Distance Transmission Plant in Utah

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 5000-hp three-phase plant covering a transmission of 36 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 15 or so 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 riveted 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 the 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 tailrace 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 1000-hp, 24-pole, three-phase generators, driven by Knight water-wheels, running at 300 revolutions per minute. The water-wheels and fittings will be furnished by the Rison Iron & Locomotive Works, of San Francisco. Water-wheels and armature are to be mounted on the same shaft, and will be supported by the same base frame and bearings. The periodicity of the current will be 60 cycles per second, and the generators will be wound for 2300 volts.

Two exciters, each of 100-kw 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 lead-covered cables, laid in ducts between the generator foundations and the wall of the building, to the generator switchboards at one end of the power-house.

The step-up transformers and the 2000 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-kw capacity, will raise the generator potential from 2300 volts to 15,000 volts, at which pressure 2000 horse-power will be transmitted to Salt Lake City. The local distribution of the balance at Ogden will be made a 2300 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-kw step-down transformers at Salt Lake City, which will deliver it at 2300 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 30 to 35 miles beyond Salt Lake City. All lines will be protected by the latest types of General Electric lightning arresters. This plant will probably be inaugurated about the 1st of November of this year.

Electric Power Transmission in Utah.