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1300 132 METROPOLITAN WATER DISTRICT An additional charge was included if fuel oil cost should exceed 75 cents per barrel at the Edison Long Beach steam plant and a credit, up to 10 per cent of the monthly bill, was allowed for high power factor. This bid WllS accepted by the District lInd an agreement entered into on July 20, 1932 with the three power companies. The actual cost to date of the power purchased under this contract is 6.25 mills per kw-hr at the Colton substation, and the lIverage delivered cost is 6.78 mills. Transmission system The transmission system was designed and built by the District to supply a maximum distributed load of 18,000 kw (24,000 horse- ~ power) but the design was such that the syst.em could be readily reinforced to carry a reasonable excess above this amount. The short period of use indicated the advisability of cheap construc- i:. tion, yet reliability was exceedingly important. A careful study was made to determine the most economic transmission line volt- age, giving due consideration to the question of steady-state sta- bility in view of the fact that a large block of power must be trans- mitted to Parker dam, a distance of 300 miles from the generating plants on the Pacific Coast. As a result of the calculations, trans- mission at 66,000 volts, the voltage at which power could be re- ceived from the Colton substation, was found to be feasible and economical, especially since it did not require the installation of a transformer bank at Colton. Selection of this transmission voltage permitted a flexible design, since one transmission line with two or three 5,000-kva synchronous condensers would be sufficient up to l,bout two-thirds the estimated maximum load of 31,000 hp and other transmission lines and condensers could be added ac-. cording to the load development. The principal features of the system are shown in Fig 10. The original 66-kv line extends from Colton via the Lakeview, Ca- bazan, Fan Hill, and Hayfield substations past the south end of the Coxcomb and over the Granite mountains to the Granite sub- station, where the 66-kv line ends about 70 miles from the aque- duct intake. An independent 66-kv line was later built on a direct line from Colton through San Timoteo Canyon to the Cabazon sub- station, making two distinct 66-kv circuits between these points. At the five substations the voltage is reduced to 33-kv to serve the power distribution system, which runs substantially parallel to the 66-kv transmission system as far as the Granite substation. Thence I (,