In this paper, one of the known interline custom power devices named Multiconverter Unified Power Quality Conditioner (MCUPQC) is designed for medium voltage level (11 kV) and improved for various power quality disturbances. An effective enhanced phase-locked loop-based control technique is applied to detect and extract the power quality disturbances for each phase separately. The performance of series compensators of MCUPQC is evaluated through extensive simulations for mitigating unbalanced voltage sags with phase jumps, swell, and interruption. Presag compensation method, which includes a novel phase-freezing algorithm, is preferred for sensitive load to mitigate the impact of phase angle jumps. The performance of shunt compensator of MCUPQC is tested for harmonic compensation, reactive power compensation, and direct current link voltage regulation. It is verified that MCUPQC, which is connected to two feeders, can compensate current and voltage imperfections successfully in these feeders according to the results obtained using PSCAD/EMTDC.