hightension

High tension is a term used in electrical engineering to describe systems, equipment, or components operated at high voltage, typically kilovolts (kV). In British English, high tension (often hyphenated as high-tension) historically described transmission lines and related apparatus, in contrast to low-tension or distribution circuits. Modern usage often simply uses high voltage.

Electric power transmission lines commonly operate from about 110 kV to 1,000 kV or more for ultra-high voltage. Distribution networks are typically in the range of 11–55 kV, while certain industrial or mining installations may use even higher. High-tension direct current (HVDC) systems exist for long-distance or underwater links, with voltages from several tens of kilovolts to over 1,000 kV.

High-tension equipment relies on robust insulation, air gaps, and creepage distances to prevent arcing. Insulators, transformers, circuit breakers, and switchgear are designed for high-voltage application and often require air-insulated, gas-insulated, or oil-filled configurations. Maintenance emphasizes insulation testing, partial discharge monitoring, and surge protection. Handling hazards include electric shock, arc flash, and the risk of unintended fault currents.

Environmental factors, soil moisture, pollution, and weather affect insulation performance. Standards from IEC, IEEE, and CENELEC govern clearances, insulation coordination, and safety practices.

The development of high-tension transmission enabled long-distance electricity distribution, with breakthroughs in transformers, insulation, and HVAC/HVDC technologies in the 20th century.