Kilovolts

Kilovolt (symbol: kV) is a unit of electric potential difference equal to 1,000 volts. It is a multiple of the volt (V) defined by the SI prefix kilo-.

In power transmission, voltages are expressed in kilovolts. Typical transmission voltages include 110 kV, 220 kV, and 400 kV. Using higher voltages reduces current for a given power, which lowers resistive losses in cables.

To enable long-distance delivery, electrical networks use step-up transformers to raise voltage for transmission and step-down transformers at substations to deliver usable voltages to consumers. Kilovolts are also used in specialized equipment and systems that require high potential differences.

Applications include X-ray machines, which commonly operate at tens to hundreds of kilovolts, as well as particle accelerators and certain industrial processes that demand high voltage. Kilovolts are encountered in laboratory power supplies, high-voltage testing, and insulation stress assessments.

Kilovolts are measured with high-voltage instrumentation. For alternating current, kV values are often specified as RMS, while direct current provides a straightforward kV value. Safety considerations are paramount at kilovolt levels, requiring adequate insulation, clearance and creepage distances, protective equipment, and strict procedures to prevent arcing and shock.

Kilovolt should not be confused with kilo-electronvolt (keV), a unit of energy used in physics. Related electrical terms include kilovolt-ampere (kVA) and kilovolt-ampere reactive (kVAR), which describe apparent and reactive power in AC systems.