Abstract: Wideband voltage sensing and measurement can provide important information for energy metering, intelligent control and relay protection of power system, which has an essential position in the fields of overvoltage online monitoring, fault warning, fault location and protection, and real-time monitoring of equipment status in grid. In the face of the ever-expanding smart grid in the future, voltage measurement has been transformed from traditional electromagnetic voltage transformers to electronic voltage transformers and optical voltage sensors, and measurement devices continue to be low-cost, low-power, miniaturized, and easy to install. Based on the current research status of broadband voltage sensing methods, this paper first introduces the contact measurement methods based on voltage dividers and optical voltage sensors and the non-contact measurement methods based on the stray capacitance-voltage division principle, GIS built-in electrode, and capacitance leakage current. Secondly, the applications of the broadband voltage sensing data in system protection, including statistics and research on typical fault waveforms, transient fault analysis of power equipment and protection means of power grid are emphatically expounded. At the same time, its applications in equipment intelligence, which is mainly divided into two parts such as line fault location and equipment insulation diagnosis, are summarized. On this basis, the challenges faced by broadband voltage sensing in terms of sensing methods, frequency and amplitude characteristics, temperature and humidity compensation, device miniaturization, and conformal integration with equipment are pointed out. Finally, further development prospects for broadband voltage sensing technology in the application in power system protection and equipment intelligence are made.