High voltage refers to electrical voltages above 1,000 V AC. In practice, this usually means voltage levels between 60 and 220 kilovolts, used for the regional distribution of large amounts of electricity. Specialized transformers and instrument transformers are essential here. The proper planning and operation of high-voltage installations require decades of experience and thorough staff training.
Why is high voltage used at all?
For electrical power transmission, the rule applies: the higher the voltage, the lower the current for the same power – and therefore the lower the losses in the lines. High voltage makes it possible to transport large amounts of energy over long distances economically. At substations, the voltage is then stepped down in stages to medium and low voltage.
Key Characteristics at a Glance
- Voltage levels typically 60 kV, 110 kV, or 132 kV
- Used in overhead lines and underground cables
- Specially designed high-voltage transformers up to 250 MVA
- Strict requirements for insulation, protection, and earthing
- An important part of regional supply grids
- Insulation coordination in accordance with IEC 60071
- Strict requirements regarding minimum clearances and earthing
Frequently Asked Questions
Where does high voltage end and extra-high voltage begin?
There are slightly different definitions internationally. In Europe, high voltage typically refers to the range from 60 kV to 150 kV. Voltages from 220 kV upward are considered extra-high voltage and are mainly used in the supra-regional transmission grid.
What safety requirements apply in high-voltage installations?
High-voltage installations are subject to strict regulations: minimum clearances, protective enclosures, earthing and short-circuiting devices, and specially trained personnel are mandatory. Maintenance is always carried out in a de-energized and earthed state.
What role do surge arresters play in high-voltage installations?
Surge arresters protect equipment from lightning strikes and switching overvoltages. They safely divert overvoltages to earth, automatically return to a high-resistance state afterward, and are therefore an indispensable element of any protection concept.
What capital equipment shapes high-voltage technology?
Power transformers, instrument and protection transformers, busbars, as well as extensive protection and control technology. Added to this are overhead lines, underground cables, and, increasingly, HVDC installations. Depending on the project, investment sums quickly reach the hundreds of millions.
Do you need high-voltage transformers or instrument transformers for a grid project? Our experts will advise you on design, protection concept, and commissioning – talk to us.