A Survey of Power System State Estimation Using Multiple Data Sources: PMUs, SCADA, AMI, and Beyond

State estimation (SE) is indispensable for the situa-tional awareness of power systems. Conventional SE is fed by measurements collected from the supervisory control and data ac-quisition (SCADA) system. In recent years, available data sources have been greatly enriched with the deployment of phasor meas-urement units (PMUs), advanced metering infrastructure (AMI), intelligent electronic devices (IEDs), etc. The integration of multi-ple data sources provides unprecedented opportunities for en-hancing the performance of SE, but also presents major challenges to resolve, including optimal multi-type-sensor co-placement, mul-tiple reporting rates and asynchronization, diverse types of meas-ured quantities, correlations between measurements, integration of online and historical data sources, and system and measurement uncertainties. This paper outlines the state of the art and research opportunities in this area by providing a comprehensive literature review and extensive discussions. It starts by presenting the moti-vations and challenges, followed by a summary of existing data sources for SE in power systems. Subsequently, for both transmis-sion system (static and dynamic) and distribution system SE, ex-isting methods are systematically reviewed and categorized based on the addressed challenges. Interesting attempts of using novel measurements in SE are also studied. Finally, the paper concludes by providing a detailed discussion on the remaining research gaps and future research directions to be explored.