The studies of the performance of feeder distance protection with multiple installations of the static synchronous compensator (STATCOM) are presented. Detailed representation of delta-connected multi-level modular converter (MMC) STATCOM is modelled and its impact on feeder distance protection is analytically studied. A real-time digital simulation (RTDS) based hardware-in-the-loop testing platform is established using practical distance relays, multiple detailed MMC STATCOM models and realistic transmission data. Different types of internal/external faults at varying locations are simulated to investigate the STATCOM's impact on feeder distance protection.