Status Evaluation Method for SMES Used in Power Grid

Abstract

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 (P <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">max</sub> ) of a SMES is restricted by the initial (standby) current (I <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> ) in the SC magnet for a specific application of SMES. To prove that P <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">max</sub> also depends on the temperature (T <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> ) 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.