For the construction of ubiquitous power stations,a new IOT molded case circuit breaker with built-in dedicated topology identification module is designed,which has the functions of characteristic current self-sending,self-receiving and self-detecting.The fast Fourier transform and power spectral density estimation are utilized to detect and distinguish the characteristic current signal.After the background fusion terminal queries the topology records of each circuit breaker,the level of each circuit breaker is determined according to the timestamp,and finally the substation area topology diagram is summarized.The proposed scheme has the advantages of small injected characteristic current,no influence on the quality of power grid,no need for the separate signal transmission and identification device,and simple circuit.The test and the operation results of the pilot station verify the feasibility and effectiveness of the method,which has certain engineering application value.