A Generating Station for the Supply of Electricity
THE CONTROL ROOM at Lots Road Power Station, Chelsea, which was opened in February, 1905. The power station supplies electricity to the District Railway, the Central London, City and South London, and London Electric Railways, East London Railway, the Whitechapel and Bow Railway, and sections of the Southern Railway, also to the London United Tramways. The illustration shows a view of the many control panels.
FOR more than thirty years Lots Road Power Station has been one of the most important buildings in London. Its four tall chimney-
From 1905, when this power station began operating, electricity has never for a moment ceased to flow from it, both night and day. Even in the small hours, when most of the Tubes and other electric railways of the London Passenger Transport Board are closed to the public, the power station is still sending out current for various purposes.
In the design, equipment and operation of a modern electric power station there are problems for the engineer’s solving, not only of a mechanical nature, but also relating to economics -
Electrical generators are expensive machines to build, install and maintain, so that, unless they are in full use every hour of the twenty-
The Lots Road plant, with its primary function of supplying power to London’s electric railways, has its “peak” periods at nine in the morning and again at six in the evening on five days of the week -
Lines on the chart from the “time” and “output” sides respectively meet at right-
On a weekday the graph will show two “mountain peaks” at nine and six o’clock coinciding with the rush hours, with “valleys” between, when the flow of traffic has lessened.
Big events in London are reflected in these graphs. Thus, the graph for Jubilee Monday, 1935, shows that the load curve rose sharply between 5.30 and 6.30 in the morning -
Another curve which indicates a piece of history is that for November 29, 1934. This was the wedding-
1,200,000 Kilowatt Hours
Lots Road Power Station may be described as a huge machine into which coal enters at one end to emerge as electricity at the other. On an average day, 750 tons of coal enter the power station dock. This amount is converted in the power station to about 1,200,000 kilowatt hours, and is distributed to thirty-
The coal arrives in lighters, which are brought into the basin when the dock gates are opened round about high water. The capacity of the dock is such that six lighters, each carrying up to 200 tons of coal, can be berthed under two transporter cranes. The grabs of the cranes unload the coal, which is then weighed and passed on to an endless belt conveyor that carries it to the elevator house. Here it is crushed, if necessary, and then lifted to the top of the building, to be stored in the bunkers over the boilers.
About 10,000 tons of coal are stored in a large circular tank on the river side, as a reserve in the event of an emergency that might arise to stop barges being worked into the dock.
AN AVERAGE LOAD of 750 tons of coal enters the dock at Lots Road Power Station every day. Coal is brought in lighters, each capable of holding 200 tons, which are berthed in the dock below two two transporter cranes for the purpose of unloading.
Water from the Thames is used for cooling purposes. It is drawn from the river by two pipes -
River water is not, of course, used in the boilers. Most of the boiler water is obtained from an artesian well, which goes to a depth of 500 ft. Some 12,000,000 lb of water are turned into steam every day. The bulk of this is in continual circulation, and is re-
The nine feed pumps, which are on the ground floor of the building, are each able to deliver 40,000 gallons per hour against a pressure of 400 lb per sq in. Three of the pumps are driven by steam and six by electricity. Two air compressors, which supply compressed air to various parts of the station for tools, cleaning apparatus, and other purposes, are also housed in the pump-
The Condensing Plant
The condensing plant and the auxiliary gear of the turbines are housed in the turbine house basement. The condensing water from the river passes through the twin shells of the condensers. The two shells have a total cooling area of 25,500 sq ft, made up of the outer surface of 1-
The starting switches and the meters for the motors are mounted on panels, the main switches being in a room extending the length of the station on the north side of the building. The controls and switchgear for the smaller motors are arranged in the same manner. Among these smaller motors are those for extracting and returning to the boiler feed-
The boiler house is on the main floor level, and is remarkable for its coolness and the absence of stokers, the boilers being fired by mechanical means. The coal, having been passed by means of conveyors into the bunkers above the boilers, is fed down pipes by gravity into the coal hopper in front of the boiler, and is carried into the furnace by a revolving chain-
ABOUT 12,000,000 LB OF WATER are converted to steam daily in the boiler house -
A fan driven by a 38 hp motor forces the air used in combustion through the grate, secondary air being introduced into the combustion chamber by a 14 hp booster fan motor. A glance into a furnace shows a white cascade of flame. The products of combustion are removed by an induced draught fan driven by a 96 hp motor. The gases pass through a dust extractor of the cyclone type, and so through the chimney stacks to the air.
Steam is developed at a pressure of 295 lb per sq in, and at a temperature of 750° F.
Each boiler has 6,470 sq ft of heating area, and is composed of 4-
In the turbine-
The most recent type of turbine has a capacity of 18,750 kilowatts, this being about three times as powerful as the original units of 6,000 kilowatts, but occupying very little more ground space. When the original units were installed they were the most powerful in Great Britain, but electricity has made great progress since those days.
In the centre of each panel is the telegraph apparatus for signalling to the driver; below, on the right, is a hand-
A GENERAL VIEW of the Generator Room at Lots Road Power Station. The maximum load of the power station is just over 100,000 kilowatts, or the equivalent of 134,000 horse-
The controls for the outgoing feeder cables are arranged in a semi-
In the middle of the semicircle of feeder controls is a telephone exchange, which enables the operator to get into communication with any part of London to which a supply of electricity is being sent.
On the right of the control-
Although the Lots Road Power Station is not the only source of power of the underground railways of London, it is the chief supply, the maximum load being just over 100,000 kilowatts, which is the equivalent of 134,000 hp.
[From part 30, published 23 August 935]