| 摘要 |
PURPOSE:To cut OFF a primary current by an AC breaker by turning OFF a GTO for constituting an inverter, and then turning ON a positive side SW of a switching element (SW) and an arbitrary negative side SW having no serial relation with the element. CONSTITUTION:When a three-phase short-circuiting fault occurs at a point A, a short-circuiting current flows at a primary side of a wound-rotor type induction machine (AM) 1. A primary current of the AM 1 abruptly becomes zero. It is detected by a short-circuiting accident detector 34, and GTOs 12-17 of an inverter 2 are turned OFF by a controller 36. Then, the u-phase positive side GTO 12 and the W-phase negative side GTO 17 are turned ON by the controller 36. Thus, charge of a capacitor 18 is discharged through the GTO 12- the u-phase secondary winding - w-phase secondary winding of the AM 1-GTO 17. And, DC components of positive and negative directions are superposed on the u-phase, w-phase secondary currents. An AC component is superposed on the primary current of the AM 1 by the DC component. The primary current can be cut OFF by an AC breaker by crossing a zero point of the primary current. |
