Abstract: The invention relates to an insulating gas mixture for replacing SF6 gas as well as its formulation method and application. The insulating gas mixture is composed of a fluorocarbon gas and a helium gas, and the formulation method includes filling the fluorocarbon gas and the helium gas in a vacuum-sealed container.

Abstract: Disclosed are a vector synchronization method and system, the method includes: converting a three-phase instantaneous value of a power grid voltage into a two-phase voltage vector component through employing a power grid voltage vector phase angle at a previous moment; subtracting the d-axis voltage vector component from the power grid vector amplitude to obtain a d-axis voltage component deviation; performing gain and integral operations on the d-axis voltage component deviation to obtain a power grid vector amplitude; performing gain, integral and proportional-integral operations on the q-axis voltage component deviation to obtain a power grid voltage vector phase angle; respectively converting the d-axis voltage component deviation and the q-axis voltage component deviation into a q-axis current compensation signal and a d-axis current compensation signal of the grid-connected inverter; and the small interference stability of the grid-connected inverter is enhanced by adopting d-axis and q-axis current com