Split-phase protection of generators

Patent metadata

Field	Value
Publication number	US-12249948-B2
Application number	US-202217823344-A
Country	US
Kind code	B2
Filing date	Aug 30, 2022
Priority date	Aug 30, 2022
Publication date	Mar 11, 2025
Grant date	Mar 11, 2025

Abstract

The present disclosure pertains to devices, systems, and methods for monitoring a generator. In one embodiment, the system may include a measurement subsystem to receive a plurality of split-phase measurements of branch currents associated with the at least one generator. A split-phase transverse differential monitoring subsystem may receive the plurality of split-phase measurements of branch currents associated with the at least one generator and may generate an offset value representing a standing split-phase current. A protective action subsystem may generate a first protective action based on the phasor operating current.

First claim

What is claimed is:

1. A system configured to monitor at least one generator, the system comprising:
a measurement subsystem to receive a plurality of split-phase measurements of branch currents associated with the at least one generator;
a split-phase transverse differential monitoring subsystem to:
receive the plurality of split-phase measurements of branch currents associated with the at least one generator;
generate a complex exponential function based on the plurality of split-phase measurements of the branch currents to shift a phase of each of the branch currents by multiplying the branch currents with the complex exponential function;
calculate a phasor operating current based on the phase-shifted branch currents; and
generate an offset value representing a standing split-phase current based on the phasor operating current; and

a protective action subsystem to generate a first protective action based on the phasor operating current and the offset value.

2. The system of claim 1 , wherein the at least one generator comprises a synchronous generator.

3. The system of claim 1 , wherein the split-phase transverse differential monitoring subsystem is configured to detect an inter-turn fault in the at least one generator.

4. The system of claim 1 , further comprising an external fault detector, and
wherein the external fault detector is configured to restrain the protective action subsystem.

5. The system of claim 1 , wherein the split-phase transverse differential monitoring subsystem is further configured to detect a current transformer failure condition and to restrain the protective action subsystem.

6. The system of claim 1 , wherein the split-phase transverse differential monitoring subsystem further comprises:
a first counter to operate after a first delay and based on a first protective element and a second protective element;
a second counter to operate after a second delay and based on the first protective element and a third protective element; and
an acceleration output based on operation of at least one of the first counter and the second counter.

7. The system of claim 6 , wherein the first protective element comprises a split-phase overcurrent protection element and the second protective element comprises forward reactive power protection element.

8. The system of claim 6 , wherein the first protective element comprises a forward reactive power element and the second protective element comprises a field second harmonic overcurrent protection element.

9. The system of claim 6 , wherein the acceleration output decreases a third subsequent time delay by at least a factor of 2.

10. A method of monitoring at least one generator, the method comprising:
receiving, using a measurement subsystem, a plurality of split-phase measurements of branch currents associated with the at least one generator;
providing a split-phase transverse differential monitoring subsystem to:
receive the plurality of split-phase measurements of branch currents associated with the at least one generator;
generate a complex exponential function based on the plurality of split-phase measurements of the branch currents to shift a phase of each of the branch currents by multiplying the branch currents with the complex exponential function;
calculate a phasor operating current based on the phase-shifted branch currents;
generate an offset value representing a standing split phase current based on the phasor operating current; and

generating, using a protective action subsystem a first protective action based on the phasor operating current and the offset value.

11. The method of claim 10 , wherein the at least one generator comprises a synchronous generator.

12. The method of claim 10 , wherein the split-phase transverse differential monitoring subsystem is configured to detect an inter-turn fault in the at least one generator.

13. The method of claim 10 , further comprising:
detecting, using an external fault detector, an external fault; and
restraining the protective action subsystem based on the external fault.

14. The method of claim 10 , further comprising:
detecting, using the split-phase transverse differential monitoring subsystem, a current transformer failure condition; and
restraining the protective action subsystem.

15. The method of claim 10 , further comprising:
providing a first counter to operate after a first delay and based on a first protective element and a second protective element;
a second counter to operate after a second delay and based on the first protective element and a third protective element; and
an acceleration output based on operation of at least one of the first counter and the second counter.

16. The method of claim 15 , wherein the first protective element comprises a split-phase overcurrent protection element and the second protective element comprises forward reactive power protection element.

17. The method of claim 15 , wherein the first protective element comprises a forward reactive power element and the second protective element comprises a field second harmonic overcurrent protection element.

18. The method of claim 15 , wherein the acceleration output decreases a subsequent time delay by at least a factor of 2.

Assignees

• Schweitzer Engineering Lab Inc

Inventors

• Chowdhury Ritwik
• Alla Matchyaraju
• Fischer Normann
• Finney Dale S

Classifications

• H02P2103/20

  of the synchronous type · CPC title

• H02P2205/01

  Current loop, i.e. comparison of the motor current with a current reference · CPC title

• H02P29/027

  the fault being an over-current · CPC title

• H02P9/006 Primary

  Means for protecting the generator by using control (control effected upon generator excitation circuit to reduce harmful effects of overloads or transients H02P9/10) · CPC title