The NP800 closed-loop backup automatic transfer (BZT) switch is suitable for uninterrupted power transfer switching in low-voltage 400V main and backup incoming line systems, ensuring the safe operation of power lines and equipment. In the past, when switching between main and backup power sources, it was necessary to first disconnect one of the power circuit breakers, wait for a delay, and then close the other power source and bus-tie circuit breaker to resume power supply. This process involved a brief delay during switching, which could not meet the requirements of systems that cannot tolerate power interruptions. The NP800 closed-loop backup automatic transfer switch effectively overcomes this drawback, enabling uninterrupted and delay-free power transfer switching. Working principle: The NP800 series low-voltage backup automatic transfer device adopts a 32-bit DSP and a 5-inch touch screen, providing a user-friendly interface and convenient operation. Other models under development include: NP807: Two incoming lines + generator (single busbar without segmentation); NP805: Two incoming lines, single busbar without segmentation (with paralleling); NP803: One incoming line, one tie + generator; NP802: Two incoming lines, one tie backup automatic transfer (single busbar segmented); NP800: Two incoming lines, one tie (with functions such as automatic transfer and recovery, automatic transfer with manual recovery, manual mode, manual closed-loop, automatic closed-loop, selective tripping, and remote control). It offers various time parameters to meet the needs of different scenarios. The NP800 low-voltage backup automatic transfer device features an interface design that displays the primary system diagram and relevant analog and digital data in real time. The NP800 series low-voltage backup automatic transfer device (integrated type) integrates voltage measurement/display, digital input/output, and network communication functions. It offers advantages such as intuitive display, simple operation, and easy maintenance. It is primarily used in distribution systems below 690V to perform fast and reliable switching between main and backup power sources, ensuring reliable production power supply. With an embedded PLC module, it provides multiple logical function options and can be adjusted according to on-site operation requirements. It can be installed at various locations within the distribution system and applied in low-voltage distribution systems of power systems, industrial and mining enterprises, public facilities, intelligent buildings, and railways. Data remote management functions are achieved through its standard RS-485 communication interface.