Extra high voltage
As high-voltage technology used electrical voltages above 300 kV are referred to ( 300,000 volts) in the electrical industry, the exact limit is not uniquely determined. The maximum voltage counts as high voltage, which covers all voltages above 1 kV. The highest possible voltages are chosen to minimize the electrical losses in long-distance transport.
Applications
Energy transfer
Use is high voltage in the form of alternating voltage in the national management level of extended power networks, the so-called transport network level, and is used in composite networks of exchange and trade of electrical energy. Common voltages, if thereby given the rms values of the line voltage are in Europe 380 kV ( 400 kV) and in parts of Russia 750 kV. The Canadian Hydro-Québec operates an extensive network of high voltage 735 kV.
When a DC voltage is the maximum voltage up to ± 800 kV ( 1.6 MV), as used in the Chinese Yunnan Guangdong HVDC. Those transmission techniques are referred to as high-voltage direct -current transmission, HVDC abbreviated or UHVDC for english ultra high voltage direct current.
Physical experiments
Maximum voltage occurs in some physical experiments, such as in linear accelerators such as the Van de Graaff accelerator.
Generation
Maximum stresses in the field of electrical power engineering are obtained by means of power transformers in power plants from the lower voltage of the electrical generators. Electric generators can generate by design no maximum voltages, so transforming the low voltage generator, some kV up to some 10 kV, by nearby machines transformers in high voltage.
They are also used in the field of high voltage tests and obtained by testing transformers and high pulse-like operations such as in artificial lightning discharges by Marx generators. In the area of physical experiments maximum voltage is generated for example by means of high voltage cascades or Van de Graaff generators.
Electrical voltages with peak values exceeding some megavolt ( MV) lead in air to partial discharges as the corona and are due to the complex and spatially extended isolation technically from about 10 MV unmanageable (= 10 million volts ).