The invention relates to the distribution network technology field, and especially relates to a modular distribution network device and a method convenient for guaranteeing. Each sub-power-grid unit comprises a subnetwork transformer and a plurality of power utilization modules. The power utilization modules are connected to the subnetwork transformer in parallel, and each power utilization modulecomprises a sub-acquisition module alternating current contactor and a load. A sub-acquisition module acquires a voltage, a current and power of an alternating current contactor, and the load is connected to a rear side of the alternating current contactor. In the invention, a workload of personnel is greatly reduced, timeliness and accuracy of a project are ensured, and effectiveness of projectfunds is improved.