The invention relates to a high-voltage direct current circuit breaker system and an energy supply device. Two power supply cables are connected in parallel and a potential in the middle of a valve layer is taken to provide working power for power electronic devices on both sides in the valve layer. The insulation requirement of the power supply cables is reduced by 50%. The safe operation margin of the power supply cables is improved. An interlayer isolation transformer adopts the method that metal casings in equipotential connection are in shielded connection with a wire to access the intra-layer low-voltage adjustable power supply transformer of a direct current circuit breaker. The potential of the access point is fixed. Partial discharge of the connecting wire at high potential is avoided. Heat dissipation of the connecting wire is realized. According to the invention, the high-voltage direct current circuit breaker system and the energy supply device can be widely and flexibly applied to the high-voltage power supply system of the high-voltage direct current circuit breaker, and are suitable for the limitation of a plurality of arrangement manners of high-voltage direct current circuit breaker equipment on the installation position and access point of the power supply transformer; the insulation requirement of the power supply cables is reduced; the equipment cost is saved; the operation reliability of power supply equipment is improved; and the high-voltage direct current circuit breaker system and the energy supply device have high and wide popularization and application values.