Abstract: In modular multilevel convertor (MMC) operation, insulated gate bipolar transistor (IGBT) or driver faults can cause sub-module short circuits, damaging devices. Studying this short-circuit condition is crucial for IGBT short-circuit protection and reliability research. This paper analyzes MMC sub-module short-circuit types and proposes, experimental platform design requirements. After optimizing short-circuit oscillations and electromagnetic interference and adjusting short-circuit circuit parasitic inductance, an MMC sub-module short-circuit experimental platform is developed. Experimental results show the developed platform meets IGBT short-circuit experiment requirements in MMC sub-module.