The invention relates to an intelligent electrical device, and belongs to the technical field of intelligent power distribution stations. The intelligent electrical device has the advantages that I/O (input/output) inserts and sampling inserts are not separated on a backboard, and card information are exchanged through connection among modules, so that the objective of mixed inserting of the I/O inserts and the sampling inserts can be achieved, and the number of the inserts can be flexibly set according to project needs; programmable logic controllers are introduced into slave modules, so that operation pressure of a programmable logic controller in a master module is relieved greatly, and system expansibility is remarkably enhanced; the programmable logic controller in the master module does not participate in early-stage data processing, so that system resources are reduced; in occasions with large external extension demands, a low-level processor can be considered so as to reduce system cost moderately.