Superconducting generators (SCG's) have many advantages such as small size, light weight, high efficiency, improvement of power system stability in steady states and s o on. SCG's with high response excitation have additional advantage of improvement of power system stability in transient states. By use of an experimental 100 kVA SCG with high response excitation whose pet name is Hesper 1, and an artificial transmission line, we carried out several experiments for power system stability. Before the experiments, we considered a block diagram for power system stability of SCG's with high response excitation, and designed automatic voltage regulators and power system stabilizer. This paper describes the above considerations and the experimental results.

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Dual-Halbach arrayed permanent magnets were produced with Dy-free Nd bonded permanent magnets whose external dimensions were 14×14×4 mm. The dual-Halbach magnets were arranged facing different poles with a 6-mm-distance air gap using the back yoke. The magnetic flux density at the center of the air gap was measured with a two-axis Hall prober and was also numerically calculated with the three-dimensional finite-element method. The flux density was enhanced with the front yoke by 9% compared to that without the front yoke. The front yoke also improved the irreversible flux loss after high temperature annealing. Furthermore, a 2.2% increase was successfully achieved with fragmentation of the back yoke. The calculated three-dimensional flux structure indicated that the efficient magnetic circuits with less stray flux to the outside enabled further enhancement of the flux density even in magnet arrays that involved complex multi-poles.

SUMMARYIn the combined-cycle power plant generators are started by using the igniting arrangement up to the ignition rotational speed of the gas turbine. On the other hand, in the case of using the superconducting generator, it is difficult to apply the igniting arrangement used to generate electricity on the combined cycle for the structure as is. We examined the induction motor starting method for the superconducting generator by using the 70-MW-class quick-response excitation superconducting model generator and the VVVF power supply. From the examination, we confirmed the ability to raise the rotational speed from 6 to 360 rpm. Moreover, it was found to be able to start 200-MW-class superconducting generators by the induction motor starting method with the analysis.