Niagara Falls 100.000-Hp. Development

36 ] Niagara Falls 100,000 Hp. Development FIG. 49—METHOD OF CONDUCTING LEADS FROM GENERATORS Six leads leave each generator. Three are main leads while the other three are the opposite ends of each phase and go through current transformers under the floor and thence to a neutral grounding- switch as shown at the right. These current trans- formers are set for differential relay protection, and there is also another set in the phase leads. There are three governor fluid pumps, centrifugal type, two of which are driven by 75-hp. 2,200-volt induc- tion motors and the third by a 220-volt direct current motor. One of the alternating-current motors is manu- ally started from the operating gallery. The second is equipped with automatic starting actuated by a float switch in the sump tank. The direct-current pump is also operated by a float switch adjusted to follow the automatic alternating-current pump. With these ar- rangements failure of governor fluid supply is practi- cally impossible. Bearing oil for all three units is handled by two 220-volt alternating-current motor-driven centrifugal pumps, both manually started. Provision is made for the addition of a third pump to be direct-current oper- ated. Oil storage is provided sufficient for one hour normal operation of the entire plant, by means of tanks supported in the roof trusses above the generating station. The 220-volt supply for lights and pumps and fan mo- tors is furnished either by a central bank of 100-kva. 2200/220-volt transformers or by an individual bank of 15-kva. 2200/220-volt transformers for each unit. Energy for lighting is distributed to panel boxes at 220 volts, single phase, a balancing coil of 1.5-kw. capac- ity being installed at each box to supply the 220/110- volt three-wire branches, all lamps being 110 volts. From the terminals of the generators cables lead to the top of the cliff, where the wires enter a terminal building containing switching, metering and protective equipment and from which lead the overhead transmis- sion lines. A control building, also located at the top of the cliff, houses the control switchboards, space being provided here for the control of possible future units and also for the control of the units in Station 3, which are now controlled from a switchboard in the old gen- erating station. Terminal Building on Cliff Above Station Owing to the fact that all of the power from the new generators was to be transmitted to a new substation at Echota (three miles distant), where complete paral- leling arrangements were to be provided, it was not considered necessary to parallel the generators at the generating station, with the duplication of switching equipment and building involved therein. Each gener- ator therefore feeds directly, without interconnection, to its own individual transmission line leading to the Echota substation, a single oil circuit breaker being interposed between the generator and the line. Ar- F.G. 50—CONTROL CABLES ARE RUN UP THE CLIFF IN CONDUIT rangements are made for synchronizing at this breaker, but it is antici- pated that the synchroniz- ing will usually be done at the substation. The terminal building is a long narrow structure lo- cated on the brink of the cliff above the generating station and was designed to house the generator oil switch and protective equip- ment, to serve as a terminal structure for the transmis- sion lines and to form part of a future step-up trans- former station. On the first floor of the terminal building are in- stalled current and potential transformers for metering- purposes and the line cir- cuit breaker. Choke coils and static absorbers for lightning protection occupy the second floor, and light- ning arresters are situated on the roof. A somewhat unique feature of this installation is the location of the circuit breaker in an opening in the wall of the building in such a way that the tanks and mechanism communicate to the outside of the building, while the terminals and high potential connections are inside. This is primarily for protection against oil fires and