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Rural electrification systems tend to use higher distribution voltages because of the longer distances covered by distribution lines (see Rural Electrification Administration). 7.2, 12.47, 25, and 34.5 kV distribution is common in the United States; 11 kV and 33 kV are common in the UK, Australia and New Zealand; 11 kV and 22 kV are common in ...
Primaries provide power at the standard distribution voltages used in the area; these range from as low as 2.3 kV to about 35 kV depending on local distribution practice and standards, often 11 kV (50 Hz systems) and 13.8 kV (60 Hz systems) are used, but many other voltages are standard.
Conventional 2-wire or 3-wire distribution lines have a higher power transfer capacity, but can require 7 poles per kilometre (12 poles per mile), with spans of 100 to 150 metres (110 to 160 yards). SWER's high line voltage and low current also permits the use of low-cost galvanized steel wire (historically, No. 8 fence wire). [ 9 ]
Sometimes it is necessary to work on parts of the substation while energized, but employees must maintain a safe distance of at least 3 metres (9.8 ft). [24] The aim to reduce substation footprints comes into conflict with ease of maintenance enhanced by including gaps where employees can safely work.
An overhead power line is a structure used in electric power transmission and distribution to transmit electrical energy along large distances. It consists of one or more conductors (commonly multiples of three) suspended by towers or poles.
Long-distance transmission (hundreds of kilometers) is cheap and efficient, with costs of US$0.005–0.02 per kWh, compared to annual averaged large producer costs of US$0.01–0.025 per kWh, retail rates upwards of US$0.10 per kWh, and multiples of retail for instantaneous suppliers at unpredicted high demand moments. [23]
In 1917, the PRR installed two 11 kV, 4.5 MVA synchronous converters at Radnor, the approximate center point of the system load. [12] This substation was located at the site of water tanks used to supply water to track pans, which supplied water to conventional steam locomotives. At some later time, the converters were shut down and removed.
11 kV until 1978 Philadelphia: SEPTA: Regional Rail system only; 11 kV until 1978 12 kV: 25 Hz United States: Rahway to Aberdeen-Matawan, New Jersey: North Jersey Coast Line, New Jersey Transit: 1978–2002 (11 kV until 1978). Converted to 25 kV 60 Hz: 12.5 kV: 60 Hz United States: Pelham, NY-New Haven, CT: New Haven Line, Metro-North Railroad ...