The distribution grid is undergoing profound changes nowadays, and state estimator has become an essential part in the control room to enable future smart grid. The newly deployed micro phase measurement units (μPMU) and advanced metering infrastructure (AMI) devices make the real-time state estimation possible for distribution system. Therefore, this paper studies the incorporation and process of the multi-source measurements and proposes a fast three-phase state estimation based on the hybrid measurements scheme. By the process of μPMU measurements, pseudo voltage measurements are added, which significantly increases the estimation redundancy. For AMI measurements, the harmonic components model is used to overcome the asynchronicity problem. An improved sequential state estimation based on the changed measurements is proposed to enable a fast estimation. IEEE 13-node and 390-node systems are simulated to verify the efficacy and efficiency of the proposed method.INDEX TERMS Advanced metering infrastructure (AMI), micro phase measurement units (μPMU), sequential state estimation, hybrid measurements scheme.