| 摘要 |
<p>A protection system for an electrical variable speed doubly fed induction machine (IM) having a stator (S) and a rotor (R), comprising instrument transformers (CTR1, CTR2, CTS1, CTS2, VTR1, VTR2) and a protection relay having at least one protection module configured:
- to detect faults from measurement values received from the instrument transformers,
- when a fault is detected, to set a start signal and start a trip timer,
- to set a trip signal when the trip timer is expired,
- to pause the trip timer and to start a reset timer when detection of the fault ends,
- when no new fault is detected before expiration of the reset timer, to hold the start signal and the trip signal in their current states,
- when no new fault is detected at expiration of the reset timer, to reset the start signal, the trip signal and the trip timer,
- when a new fault is detected before expiration of the reset timer, to stop pause of the trip timer.</p> |
