A power management system, notably for a dual travelling wave tube amplifier, includes: two travelling wave tubes, each comprising one Anode Zero electrode, and an electronic power conditioner, the power management system being implemented in said electronic power conditioner and including power management means associated with each travelling wave tube, configured for setting the Anode Zero electrode voltage to a determined minimum value when a sleep mode is activated, the power management means maintaining the travelling wave tube operating power at a value below its nominal working range. A sleep mode can advantageously be combined with an RF-Mute mode.