Fig 1.
Structure of the CVT system.
Fig 2.
(a)With speedy saturation damper. (b) With resonance-type damper.
Fig 3.
Element parameter calculation for the compensation reactor.
Table 1.
Parameter values of the common elements of the two CVTs.
Table 2.
Parameter values of the two different dampers.
Fig 4.
Resonant circuits of the CVT with a speedy saturation damper.
(a) Resonant circuit 1. (b) Resonant circuit 2. (c) Resonant circuit 3.
Table 3.
Resonance modes of the CVT with a resonant damper.
Fig 5.
Resonant circuits of the CVT with a resonant-type damper.
(a) Resonant circuit 1. (b) Resonant circuit 2. (c) Resonant circuit 3. (d) Resonant circuit 4. (e) Resonant circuit 5.
Fig 6.
Frequency response characteristics of the ratio of the CVT with a speedy saturation damper.
(a) Amplitude-frequency characteristic. (b) Phase-frequency characteristic.
Fig 7.
Frequency response characteristics of the ratio of the CVT with a resonant-type damper.
(a)Amplitude-frequency characteristic. (b) Phase-frequency characteristic.
Table 4.
Comparison of the resonance modes of CVT with a resonant damper.
Table 5.
Prediction of the resonant modes of the CVT with a speedy saturation damper.
Table 6.
Design of the neural networks for the fitting of the frequency response characteristics.
Fig 8.
Fitting results of the amplitude of the transformation ratio.
Table 7.
Fitting results of the amplitude-frequency response of CVT with a speedy saturation damper.
Fig 9.
Structure of the experimental platform with a step-up transformer.
Fig 10.
Arrangement of part of the experimental setup.
Fig 11.
Amplitude-frequency response of the RCVT transformation ratio.
Table 8.
RMS values of the measured harmonic voltages.
Table 9.
Parameters of the two step-up transformers.
Fig 12.
Impendence-frequency characteristics of the experimental platform circuit.
Fig 13.
Harmonic voltage measurement error of the 35-kV CVT.
Table 10.
Harmonic measurement error of the 35-kV CVT.
Fig 14.
Amplitude-frequency characteristic of the transformation ratio of the 35-kV CVT.
Fig 15.
Simulation model of the back-to-back HVDC system.
Table 11.
Rated element parameters of the two filters.
Fig 16.
The waveforms of the filter currents and CVT voltages.
Fig 17.
Total harmonic voltage of the 500-kV bus.
Table 12.
Comparison of the amplitude of the individual harmonic voltage.
Table 13.
Comparison of the RMS values of the individual harmonic voltages.
Table 14.
Prediction of the resonance frequencies.
Table 15.
Comparison of the harmonic measurement error.