Status Evaluation Method for SMES Used in Power Grid

Superconducting magnetic energy storage (SMES) is expected to be utilized in the power grid for dynamic power compensation. However, a SMES status such as magnet current (including parameters of power conditioning system) and temperature of superconducting (SC) magnet will restrict the output capability of SMES. This paper proposes a new method to evaluate SMES status, which will guarantee the dynamic thermal stability of SC magnet applied in power grid. First, it is generally analyzed that the output capability (Pmax) of a SMES is restricted by the initial (standby) current (I0) in the SC magnet for a specific application of SMES. To prove that Pmaxalso depends on the temperature (T0) of the SC magnet, the thermal characteristics of the SC magnet is simulated with a 5 MJ SMES model. Based on these restricted conditions and the simulation results, a SMES status evaluation method (SSEM) is constructed and implemented. Then, with combination of test data gotten from open-loop experiments of a real 150-kJ/100-kW conduction-cooled SMES, the presented SSEM is realized by simulation in MATLAB/Simulink, the simulation results preliminarily verify the feasibility and effectiveness of SSEM. Furthermore, SSEM is applied to dynamic experiments, whereas the 150-kJ/100-kW SMES is set for damping power oscillation after the short-circuit fault in a physical simulated power grid. The proposed SSEM presents a potential way to optimize SMES operation in the power system.