Electricity: motive power systems – Synchronous motor systems – Synchronization systems
Patent
1989-09-20
1990-12-11
Shoop, Jr., William M.
Electricity: motive power systems
Synchronous motor systems
Synchronization systems
318712, 318700, 318798, H02P 540
Patent
active
049773623
ABSTRACT:
During the run-up of high-power synchronous machines (6), such as those used in pumped storage plants, in gas turbines sets and so forth, unwanted alternating currents with slip frequencies between those of the phase swings and the nominal frequency (50 Hz) of the synchronous machine (6) can also occur in the disturbed condition in addition to low-frequency plant-specific phase swings. These alternating currents are induced in the field windings of the synchronous machine (6) as a consequence of an unwanted asynchronous starting and can lead to inadmissible heating of the synchronous machine and to overvoltages in the field circuit. Alternating voltages (U1) associated with the slip frequencies are detected from use of a sensing resistor (4) in the exciter current (i.sub.f) of the synchronous machine (6), separated from the high-voltage potential in an isolating converter (10), subsequently filtered in a bandpass filter (11), controlled for constant amplitude in a function generator (12), triggered in a Schmitt trigger (13) and selected by means of two timing sections (15, 16). If a slip frequency is detected uninterrupted for longer than a predeterminable minimum period (T3), field and high-voltage switches (5, 7) in the circuits of the synchronous machine (6) are opened by a RS flip-flop (19).
REFERENCES:
patent: 3748555 (1973-07-01), Hoffman
patent: 3784896 (1974-01-01), Lakota
patent: 3793572 (1974-02-01), Canay
patent: 4366427 (1982-12-01), Walker et al.
patent: 4572995 (1986-02-01), Enami
patent: 4616166 (1986-10-01), Cooper et al.
patent: 4659973 (1987-04-01), Stich
patent: 4812729 (1989-03-01), Ito et al.
"Frequenzanlauf fur Pumpspeicherwerke--Moglichkeiten und Optimierung", Bose, Canay and Simond, 7/8-83.
Asea Brown Boveri Ltd.
Cabeca John W.
Shoop Jr. William M.
LandOfFree
Protection method and protection device for detecting asynchroni does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Protection method and protection device for detecting asynchroni, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Protection method and protection device for detecting asynchroni will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-391887