Current Transformers for 800kV Voltage Class

The 800kV current transformer (CT) is crucial equipment in ultra-high voltage (UHV) AC grids. It is primarily used for current measurement, electrical energy metering, and relay protection in 800kV-class power systems, providing highly accurate current signal support for the safe and stable operation of the power grid. Based on the principle of electromagnetic induction, it utilizes the electromagnetic coupling between the primary and secondary windings to transform large currents in the high-voltage circuit into standard small currents (5A or 1A), facilitating subsequent instrument measurement and the operation of protection devices. Structurally designed to accommodate UHV operating conditions, its insulation predominantly utilizes SF₆ gas or oil-paper composite insulation. The casing is hermetically sealed and features excellent electromagnetic compatibility (anti-interference), resistance to extreme high and low temperatures, and robust seismic performance. The equipment is categorized into metering classes and protection classes to meet the respective demands for high-precision metering and large dynamic range protection. It is widely applied in 800kV UHV substations, converter stations, and high-voltage outgoing circuits. During operation, an open circuit on the secondary side is strictly prohibited, and regular monitoring of insulation performance and equipment status is required to ensure its stable and reliable operation.