Abstract Measure of electric field signals through sensors to get inversion voltage value is a reliable method for monitoring the operation of transmission lines. This article proposes a method for measuring vector electric field and inverting the voltage of each phase of transmission lines. A spherical vector electric field measurement sensor is designed to achieve single point electric field measure through single sensor to obtain the three-phase voltages of transmission lines. Due to the rich electric field energy contained in the electric field measurement points, an electric field energy harvesting equipment is designed to achieve integrated measurement and supply. The experimental testing of the spherical vector sensor and electric field energy harvesting device show that the phase shift of the spherical vector sensor is about 1.3°, therefore the response speed is fast. The inversion results have good linearity and can achieve 10MHz broadband measurement. The energy harvesting equipment can achieve a considerable output at the same measurement point.