Silicon Controlled Rectifier (SCR)-Embedded Identification of Field Winding, Damper Bar, and Eccentricity Faults in Wound Field Synchronous Machines

초록

It is crucial to detect faults in the rotor of wound field synchronous machines (WFSM) such as shorted field winding turns, broken damper bars, and rotor eccentricity, before they escalate into failures that cause forced outage of the machine. The off-line test methods available for detection of these faults require machine disassembly and/or physical access to the machine, which lead to high maintenance costs. On-line monitoring options require installation of sensors on the stator bore or on the machine frame and are not sensitive to the above-mentioned rotor faults. In this paper, a new test concept for remote and automated detection of WFSM rotor faults is proposed as a solution. The silicon-controlled rectifier (SCR) of the static field excitation system is used for injecting test signals into the rotor winding for testing, whenever the WFSM is de-energized. It is shown that the equivalent rotor impedance at 6 times the 50/60 Hz supply frequency at varying saturation levels of the core can be used for reliable detection and classification of shorted field winding turns, broken damper bars, and eccentricity. An experimental study on 20, 30, and 100 kVA WFSMs under the 3 fault conditions is given to validate the effectiveness of the proposed test method. © 1972-2012 IEEE.

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