The utility model discloses an adaptive zero line broken string protection device and system, wherein adaptive zero line broken string protection device includes three -phase phase line lambda line terminal, three -phase phase line terminal outgoing lines, zero line lambda line terminal, zero line terminal outgoing lines, current transformation ware, three voltage changer, data processing unit, switch quantity output circuit and circuit breaker, the current transformation ware concatenates between zero line lambda line terminal and the zero line terminal outgoing lines, link to each other through the circuit breaker between three -phase phase line lambda line terminal and the three -phase phase line terminal outgoing lines, each phase line lambda line terminal constitutes a set of terminal group with zero line lambda line terminal and inserts the input of a voltage changer, the output and the current transformation ware of three voltage changer insert the data processing unit, and the data processing unit passes through the switch quantity output circuit and links to each other with the circuit breaker. The utility model also discloses a adaptive zero line broken string protection system. Adopt the utility model discloses, can realize disconnected null detection function, the effective reduction because the zero line broken string moves the loss that causes.