Current Transformers for 550kV Voltage Class

The 550kV current transformer (CT) is core primary equipment in extra-high voltage (EHV) 550kV power transmission and transformation systems. Serving as a crucial current monitoring and protection component for cross-regional grid interconnections, grid integration of major power plants, and power supply of hub substations, it is widely deployed at busbars, main transformer incoming and outgoing lines, and transmission line terminals/tie stations within 550kV hub substations. Based on the principle of electromagnetic induction, it transforms large primary currents ranging from thousands to tens of thousands of amperes into standard secondary currents of 5A or 1A according to a standard transformation ratio. This provides high-precision and linearized current signals for secondary measurement and control, commercial metering, and relay protection systems. Furthermore, it achieves electrical isolation between the primary EHV circuit and the secondary low-voltage circuit, fundamentally ensuring the safety of secondary equipment and the personal safety of operation and maintenance (O&M) personnel. It is essential foundational equipment for achieving safe and stable operation, rapid fault clearing, and fair and accurate metering in the 550kV EHV power grid, directly determining the power supply reliability and operational safety of the EHV grid.