I. Introduction
Smes systems can store energy in superconducting magnets and are commonly utilized for a variety of power system applications [1], [2]. Generally, a HTS SMES system consists of a HTS magnet, cryogenic system, power conditioning system (PCS), and monitor and control system (MCS). Fig. 1 shows the basic topology of a typical SMES system with a HTS magnet connected to a voltage source converter (VSC) via a DC-DC chopper [3]. During the power exchange process, the voltage across the HTS magnet is produced via switching operations of the PCS semiconductor devices and is characterized by steep rising edge and high frequency. Per the high frequency transient model, PWM voltage is not distributed evenly between windings. This transient overvoltage can endanger the insulation and even lead to SMES operation failure. To this effect, understanding the electromagnetic transient interaction between the HTS magnet and the PCS is critical in regards to the successful design of SMES magnet insulations. This type of research can also provide a basis from which to investigate transient suppression methods.
Topology of VSC SMES.