TECHNICAL AND ENERGY INDICATORS OF MEAN POWER AUTONOMOUS SYNCHRONOUS GENERATOR

Authors

DOI:

https://doi.org/10.20535/1813-5420.4.2019.200472

Keywords:

autonomous generating unit, synchronous generator, nodes of forced capacitive switching

Abstract

The energy performance improving of the exciter by switching on the zero diodes and capacitors leads to a
significant change in the harmonic composition of the excitation voltage. The study investigates the harmonic
composition of the excitation voltage of synchronous generators with asymmetrical bridge exciters using the units
of forced capacitive switching. To determine the harmonic composition of the excitation voltage, we decompose the
experimental curve into a Fourier series and expressions for calculating the harmonic components. The results of
the spectral analysis indicate that the excitation voltage at the rated mode of the generator contains a significant third
harmonic, which is 66 percent of the amplitude of the first harmonic. The significant value of the third harmonic is
due to the large angles of control of the exciter thyristor in the nominal mode of operation of the synchronous
generator. Due to the significant third harmonic, the secondary winding of the rectifier transformer must be
connected to a triangle. The presence of even harmonics is caused by the voltage asymmetry with respect to the
abscissa.
A non-symmetrical bridge exciter with a forced capacitance switching unit for a synchronous generator has
been developed, which provides improved energy performance during its nominal operation. The scheme of control
of the bridge asymmetrical exciter of the synchronous generator with the node of forced capacitive switching for the
rated mode of operation, as well as in the mode of the field suppression at short circuits of the stator windings has
been described.
The comparative estimation of the suppression modes of the field at a short circuit of the windings of the
generator stator with the possible mode of inverting the exciter and using the node of forced capacitive switching
has been carried out. Experimental studies have confirmed the calculated dependences of the modes of the magnetic
field suppression. The analysis of experimental dependencies shows that the units of forced capacitive switching
provide a higher speed of the field suppression modes, regardless of the presence and magnitude of the supply of
voltage the exciter.

References

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Published

2020-03-05

Issue

Section

MONITORING, DIAGNOSTICS AND MANAGEMENT OF ENERGY PROCESSES AND EQUIPMENT