The invention discloses a high-voltage-end energy supply system for monitoring the total branch current of an operation dry-type reactor star frame, and belongs to the field of power technology. The energy supply system includes a high-voltage-end energy supply system, a current transformer online energy extraction system, and a rectification voltage regulator device. When the grid is operating normally or in a transient process, the current transformer online energy extraction system stably outputs a DC voltage, and the high-voltage-end energy supply system is in a power-reduction hot backupstate. When the grid is first energized or the grid current is less than the wakeup current of the current transformer online energy extraction system, the high-voltage-end energy supply system controls a converter at full power to stably outputs +/-5V voltage. The power of the high-voltage-end energy supply system is dynamically controlled by a low-voltage zone merging unit according to a currentmeasurement value. The hybrid power supply system does not have a current dead zone and a wakeup time problem, can meet the continuous stability requirements of an operation dry-type reactor star frame total branch current monitoring system for the power supply. The multipath energy sources can provide higher work reliability for the hybrid power supply system.