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Corona and resistive losses can be estimated using a mathematical model. At higher voltages, where more than 2,000 kV exists between conductor and ground, corona discharge losses are so large that they can offset the lower resistive losses in the line conductors. While power loss can also be reduced by increasing the wire's conductance (by increasing its cross-sectional area), larger conductors are heavier and more expensive. Many devices that we use need more power to function than DC can provide. In any AC line, conductor inductance and capacitance can be significant. The 287.5 kV (Hoover Dam to Los Angeles line, via Victorville) and 345 kV (Arizona Public Service (APS) line) are local standards, both of which were implemented before 500 kV became practical. Subtransmission circuits are usually arranged in loops so that a single line failure does not stop service to many customers for more than a short time. Substation transformers reduce the voltage to a lower level for distribution to customers. It is uneconomical to connect all distribution substations to the high main transmission voltage, because that equipment is larger and more expensive. O'Brien, Terrence. "Google's Project Glass gets some more details." Engadget.

Not everyone has greeted the news of Google Glass with enthusiasm. It worked by detecting the vibrations on a pane of glass caused by the sound pressure generated by voices within the target room. This efficiency delivers a larger proportion of the generated power to the loads. High-voltage power transmission allows for lesser resistive losses over long distances. Transmitting electricity at high voltage reduces the fraction of energy lost to Joule heating, which varies by conductor type, the current, and the transmission distance. As of 1980, the longest cost-effective distance for DC transmission was 7,000 kilometres (4,300 miles). For AC it was 4,000 kilometres (2,500 miles), though US transmission lines are substantially shorter. Current flowing through transmission lines induces a magnetic field that surrounds the lines of each phase and affects the inductance of the surrounding conductors of other phases. Three-phase lines are conventionally strung with phases separated vertically. There are two types of circuits: feeder and branch. Classic types of hardware like wood and brass knobs never lose their appeal. Like transmission, subtransmission moves relatively large amounts of power, and like distribution, subtransmission covers an area instead of just point-to-point.

Subtransmission runs at relatively lower voltages. Similarly, an unbalanced load may occur if one line is consistently closest to the ground and operates at a lower impedance. Today, the Hangzhou Bridge, which opened in May 2008 after nine years of planning and construction, holds the honor as China's longest bridge. If you vehicle has a dead battery, it may not start or may have difficulty starting, have dimmed or flicking lights or an issue with the sound system. The arm might have the same capabilities of a human arm, with shoulder, elbow and wrist articulation, or it may have many more joints, allowing the operator to reach places he wouldn't be able to get to on his own. Unbalanced inductance among the three conductors is problematic because it may force the middle line to carry a disproportionate amount of the total power transmitted. While subtransmission circuits are usually carried on overhead lines, in urban areas buried cable may be used.

Many cable companies now offer telephone and Internet along with TV. A 1992 U.S. Supreme Court decision held that companies with no actual physical presences in a particular state -- a store at the local mall, or a regional distribution center for example -- weren't required to charge sales tax for items they ship to that state. This distribution is accomplished with a combination of sub-transmission (33 to 138 kV) and distribution (3.3 to 25 kV). Voltages of 69 kV, 115 kV, and 138 kV are often used for subtransmission in North America. The lower-voltage subtransmission lines use less right-of-way and simpler structures; undergrounding is less difficult. No fixed cutoff separates subtransmission and transmission, or subtransmission and distribution. In general, losses are estimated from the discrepancy between power produced (as reported by power plants) and power sold; the difference constitutes transmission and distribution losses, assuming no utility theft occurs. The terminal characteristics of the transmission line are the voltage and current at the sending (S) and receiving (R) ends. Voltage is stepped down before the current is sent to smaller substations. You see a wide meadow full of sunshine streaming down into the tall grass up ahead.

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