4 Power transmission

4 Power transmission - Power Transmission Power is...

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Power Transmission Power is transmitted through transmission lines at different voltages. Usually, the longer the distance over which the power must flow, the higher is the transmission voltage. At the local distribution level, the three-phase, phase-to-phase voltage employed ranges from 25 to 40 kV. Of course, at the residential level the 3-phase voltage is transformed down to 120 volts, single phase. For very long distances and large power levels, 400, 500 and 735 kV are standards followed in North America and Europe. Generally, high voltage levels lower the current magnitude and therefore reduce the transmission losses, increasing the overall efficiency of getting energy from the sources to the consumers. At the generating level, the voltage is relatively low, of the order of 10 kV, given that insulation inside the closed space of a power plant is difficult for higher voltage levels. In addition, the flux densities inside the iron rotor and stator of the generating units are limited by the magnetic saturation properties of ferromagnetic materials. This limitation then restricts the level of the voltages induced in the machine
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4 Power transmission - Power Transmission Power is...

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