Active filters and advanced static VAr compensators (STATCOM) are hampered in their application at medium voltage levels (e.g. 13.8 kV) due to the need for a line-frequency interface transformer. A novel per-phase approach eliminates the need for a line-frequency transformer by series connection of slow-switching converters and a fast-switching PWM converter. The slow-switching converters operate in voltage-mode to counteract the utility voltage while the PWM converter operates in a current-control mode to control the injected current. Experimental results of a DSP-based laboratory prototype operating in steady state are presented to establish the concept validity. EMTP simulations address many practical aspects of this scheme-operation under steady stare conditions; transients such as startup, faults, sudden over- A nd under-voltages; and DC bus voltage regulation. The simulation results demonstrate the technical feasibility of this approach for implementing it in utility systems.