Voltage-Sourced Converter (VSC) based Synchronous Static Compensator (STATCOM) is used for voltage regulation in transmission and distribution system. On the other hand, Modular Multilevel Converter (MMC) based STATCOM (M-STATCOM) is now well accepted technology in large STATCOM applications due to high modularity, scalability, and low generation of harmonics. This paper investigates negative sequence component elimination with M-STATCOM on New York Power Authority (NYPA)'s Convertible Static Converter (CSC) along with three-bus AC system on Marcy substation in the State of New York. Real Time Digital Simulator (RTDS) is used for providing the results of the study.