In the electrical engineering a is electrical voltage as a high voltage (English High Voltage , HV) denotes whose values as agreed in 1000 volts exceed (1 kV) AC and 1500 V (1.5 kV) voltage. Electrical voltages that do not exceed the specified limit values are referred to as low voltage . Furthermore, non-standardized conceptual subdivisions of high voltage into the sub-terms medium voltage , high voltage and maximum voltage are common.
In the space application area (including unmanned satellites ), the high voltage limit is set at 150 V. The reason is that an electrical breakthrough at low gas pressure - as in orbits close to the earth - can be triggered even at lower electrical field strengths than at normal pressure . This is a consequence of Paschen's law .
- Medium voltage of 3 kV, 6 kV, 10 kV, 15 kV, 20 kV, 30 kV
Areas of application are in medium voltage networks for supplying individual parts of the city or several localities. Medium-voltage customers are small to medium-sized industrial companies or other facilities such as airports, hospitals and the like. Small power plants such as small hydropower plants or wind power plants feed in at this level.
- High voltage of 60 kV, 110 kV
Areas of application are the supply of small cities and the overland supply. The connection of smaller power plants and larger industrial companies also takes place at this voltage level.
- Maximum voltage of 220 kV, 380 kV, 500 kV, 700 kV, 1150 kV
These are used for large-scale supply, form interconnected networks for supraregional energy exchange and the connection of large power plants.
The so-called rated voltage must be distinguished from the nominal voltage . It indicates the maximum voltage for which the insulation of switching devices must be designed. The rated voltage is always above the nominal voltage.
Generation and use
For artificial generation of high voltage band generators , electrostatic generators , influence machines , Tesla transformers , induction coils and Marx generators used. In power plants, the alternating voltage generated in generators is converted to high voltage by means of transformers (see substation ).
In addition to its use for energy transport, high voltage is used in the following areas, among others:
- Generation of ignition sparks ( ignition coil in gasoline engines , in oil or gas heaters or in lighter )
- Testing of electromagnetic compatibility and immunity to interference of components and devices (see also Marx generator )
- Anode voltage in cathode ray tubes (e.g. televisions , X-ray tubes ) or in ionization tubes
- Acceleration of electrons and ions (e.g. in particle accelerators )
- In electric fences
- In electric fly swatters
In contrast to the low voltage at which the current flow, direct contact with the participating leaders is necessary, it can be at high voltage even at the non-contact approach to uninsulated voltage power lines to flashover not sufficiently isolated or damaged power cables to or at voltage breakdown occur, which arcs occur, the persons involved or other living creatures (with adequate amperage hurt) life-threatening or fatal or fires can cause objects.
For this reason, the specified safety distances must be observed, which regulate the required minimum distances, which increase with the level of voltage.
- IEC 60050: 601-01-27 "high voltage". In: IEV , International Electrotechnical Dictionary. DKE, accessed on January 12, 2020 .
- Hilgarth Flosdorff: Electrical energy distribution . Teubner, 2003, ISBN 3-519-06174-0 , chap. 1 , p. 2 .
- Space engineering - Spacecraft charging. European Cooperation for Space Standardization (ECSS, ESA), July 31, 2008, accessed on January 16, 2016 (= Chapter 8 .: High voltage system requirements).
- Qualification for work on vehicles with high-voltage systems. In: DGUV Information 200-005. German Statutory Accident Insurance , April 2012, accessed on November 27, 2019 .
- Siemens: Fire protection guide: Technical fire protection and fire protection systems . John Wiley & Sons, 2016, ISBN 978-3-89578-948-9 ( limited preview in Google Book Search [accessed December 6, 2016]).
- Hans Kemper: dangers d. Insert. - Electricity (fire brigade expertise) . ecomed-Storck GmbH, 2015, ISBN 978-3-609-69792-5 ( limited preview in the Google book search [accessed on May 26, 2016]).
- Kögler / Cimolino: Standard rules of use: Electric current in use . ecomed-Storck GmbH, 2014, ISBN 978-3-609-69719-2 ( limited preview in the Google book search [accessed on May 26, 2016]).