SMES refers to the use of an inductor wound by a superconducting coil to store electrical energy. Due to the zero resistance characteristic of superconductivity, it has a flow capacity that exceeds the normal conduction by two orders of magnitude. Therefore, SMES has a relatively high energy storage density, with an energy density of up to 108J/m3, and there is no Joule loss when passing through direct current. In SMES, the energy of the superconducting coil is stored in direct current form, and participating in power regulation of the power grid is achieved through energy exchange with the power grid through a converter. SMES devices are generally composed of four important components: superconducting magnets and low-temperature dewars, converter systems, refrigeration equipment, and measurement and control systems.

Compared to other energy storage SMES, it has the following characteristics:

(1) The response speed is fast, which can reach 1-5ms, which is a response speed that other energy storage systems cannot achieve. This allows for quick response to faults in the power grid and power compensation;

(2) Through the converter, four-quadrant controllable power exchange can be achieved, and active and reactive power can be exchanged simultaneously;

(3) It can output high power in a short period of time, with low energy loss and high system efficiency; The output power density is very high, and due to the absence of Joule heat caused by DC resistance, the energy efficiency is very high, ideally reaching over 95%.

The key issue in the widespread application of SMES currently lies in the breakthrough of superconducting materials, including their performance and cost; And the progress of low-temperature refrigeration technology.