Which type of transformer is essential for measuring high voltage currents accurately?

The type of transformer essential for measuring high voltage currents accurately is a current transformer. Current transformers are specifically designed to produce a reduced current that is proportional to the higher current in its primary circuit. This allows for safer and more manageable measurements of high voltage currents by stepping down the current to a lower, more measurable level.

Current transformers facilitate the use of standard metering devices by providing a scaled-down version of the primary current, which can then be measured without the need for specialized equipment that can directly handle the high voltages. This is crucial in electrical systems, especially in substations and industrial settings where ensuring safety and accuracy in measurement is paramount.

In contrast, voltage transformers are designed to reduce high voltages to lower levels for measurement and protection but do not measure current directly. Auto-transformers have a single winding and are typically used for voltage regulation rather than current measurement. Step-up transformers increase voltage and are not suited for the task of measuring current. Thus, the current transformer stands out as the essential type for accurately measuring high voltage currents.