High response excitation control of superconducting generator for stability of superconducting field winding

Superconducting generators (SCGs) can improve power system stability in steady state and also in transient state with a high response excitation. The authors designed and made an experimental 100 kVA SCG with high response excitation and carried out several experiments for power system stability using an artificial transmission line. In this paper, a high response excitation control of SCG considering stability of the superconducting field winding is discussed and tested. A proposed control system has limiter (over excitation limiter) functions for not only the field current but also for its differential value (voltage). These factors affect a design of the field windings. Transient stability tests were performed by using the test generator and the artificial transmission lines with and without the proposed excitation control. The effects of the proposed control on the transient stability were studied.