A virtual instrument for on-line evaluation of alternator's shaft misalignments through ICSVA (internal current space-vector analysis)

This paper shows a laboratory implementation of a new on line monitoring method for detection of synchronous generator (SG) rotor eccentricities (REs). A 17kVA 4-pole wound-rotor salient-pole SG with reconfigurable stator poles and a regulated mechanical flange has been instrumented with Hall sensors, data acquisition board (DAB), and a LabView virtual instrument (VI) for RE detection through internal current space vector analysis (ICSVA). The ICSVA has been theoretically described in a companion paper; test-bed and experimental performances are described here. REs make rise loop currents in the SG's stator with parallel connections. Pole currents are transformed through a Fortescue's matrix, and 2(p±1) pole current space vectors are used for RE detection in 2p-pole SGs. The analytical signals were elaborated by direct detection of maximum and minimum amplitude of cardioid trajectories, and in alternative, by FFT. Both the methods were tested and discussed. A commissioning procedure for practical method set-up is also presented.

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