Stator-rotor protection for multi-phase wound-rotor machines
AssigneeSchweitzer Engineering Laboratories, Inc.
InventorsBogdan Z. Kasztenny, Dale S. Finney, Douglas I. Taylor
Life of this patent
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Abstract
The present disclosure pertains to systems and methods for protecting multi-phase wound-rotor electric machines in an electric power delivery system. Protection of these machines uses an equivalent rotor current determined using rotor current signals, and an equivalent stator current determined using stator current signals. The equivalent rotor and stator currents are independent of the voltage and rotor position signals and are used in protection elements to determine a fault condition.
Claims18
A system for protecting a multi-phase wound-rotor electric machine of an electric power delivery system, comprising:
- a protective device in electrical communication with the multi-phase wound-rotor electric machine, comprising:
- a stator current sensor component to obtain stator current signals corresponding with stator currents from each phase of a stator of the multi-phase wound-rotor electric machine;
- a rotor current sensor component to obtain rotor current signals corresponding with rotor currents from each phase of the rotor of the multi-phase wound-rotor electric machine;
- a processor;
- and,
- a computer-readable storage medium in communication with the processor, the stator current sensor component and the rotor current sensor component, comprising instructions that when operated cause the processor to:
- calculate an equivalent stator current as a function of the stator current signals from each phase of the stator;
- calculate an equivalent rotor current as a function of the rotor current signals from each phase of the rotor;
- execute a protection element to determine a fault condition based on a relative comparison of the equivalent stator current and the equivalent rotor current, and to assert a fault signal upon determination of the fault condition;
- and
- implement a protective action based on the assertion of the fault signal.
A method for protecting a multi-phase wound-rotor electric machine of an electric power delivery system, comprising:
- obtaining stator current signals corresponding with stator currents from each phase of a stator of the multi-phase wound-rotor electric machine;
- obtaining rotor current signals corresponding with rotor currents from each phase of a rotor of the multi-phase wound-rotor electric machine;
- calculating an equivalent stator current as a function of the stator current;
- executing a protection element to determine a fault condition based on a relative comparison of the equivalent stator current and the equivalent rotor current, and to assert a fault signal upon determination of the fault condition;
- and
- implementing a protective action based on the assertion of the fault signal.
Dependencies are inferred from the claim text.