Browsing by Author "Wallace, R"

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    A fault protection scheme for series active power filters
    (IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 1999) Moran, LA; Pastorini, I; Dixon, J; Wallace, R
    A protection scheme for series active power filters is presented and analyzed in this paper. The proposed scheme protects series active power filters when short-circuit faults occur in the power distribution system. The principal protection element is a varistor, which is connected in parallel to the secondary of each current transformer. The current transformers used to connect in series the active power filter present a low-magnetic saturation characteristic increasing current ratio error when high currents circulate through the primary winding, thus generating lower secondary currents. In this way, the power dissipated by the varistors is significantly reduced. After a few cycles of short-circuit currents flowing through the varistor, the gating signals applied to the active power filter switches are removed and the pulsewidth-modulation (PWM) voltage-source inverter (VSI) is short circuited through a couple of antiparallel thyristors.
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    Series active power filter compensates current harmonics and voltage unbalance simultaneously
    (INST ENGINEERING TECHNOLOGY-IET, 2000) Moran, L; Pastorini, I; Dixon, J; Wallace, R
    An active power filter connected in series to the power distribution system is presented and analysed, The series active power filter is implemented with a three-phase PWM voltage-source inverter and operates with a resonant LC passive filter connected in parallel to the power lines. The proposed scheme is able to simultaneously compensate current harmonics, the fundamental negative and zero sequence voltage components generated by the voltage source unbalance, and also eliminates the zero sequence current harmonic components that circulate through the neutral conductor. The active power filter is discussed in terms of the principles of operation under steady-state and transient conditions. The design and implementation of the power and control circuits are reported. Key predicted results are verified experimentally on a 5kVA prototype model.