Design and implementation of a hybrid series active filter system

A hybrid series active filter system has been designed, built and installed at Beverly Pump Station in New England Electric Power Company utility for 765 kVA, 480 V adjustable speed drive load to comply with IEEE 519 recommended harmonic standards. The series active filter has a small rating-35 kVA which is 4% of the load kVA-and is controlled by a synchronous reference frame (SRF) based controller. The hybrid series active filter system is controlled to act as a “harmonic isolator” between the supply and load. This paper discusses the SRF controller implementation issues, design considerations of the series coupling transformer and protection issues of the small rating series active filter inverter. Operation of the series active filter under off-tuned passive filter conditions is investigated. The effectiveness of the series active filter to provide harmonic damping and the use of simpler and low cost passive filter structures such as power factor correction capacitors is demonstrated by laboratory experimental results. Field installation results demonstrate the practical and economic viability of hybrid series active filter systems for harmonic compensation of large nonlinear loads to comply with IEEE 519 recommended harmonic standards