US 11,946,966 B1
Selective stator ground fault protection using positive-sequence voltage reference
Ritwik Chowdhury, Charlotte, NC (US); Jason Andrew Young, Smith Falls (CA); Jon Steinmetz, Hurricane, WV (US); Rogerio Scharlach, Sandy Springs, GA (US); and Satish Samineni, Malvern, PA (US)
Assigned to Schweitzer Engineering Laboratories, Inc., Pullman, WA (US)
Filed by Schweitzer Engineering Laboratories, Inc., Pullman, WA (US)
Filed on Feb. 20, 2023, as Appl. No. 18/171,475.
Int. Cl. G01R 31/08 (2020.01); G01R 31/52 (2020.01)
CPC G01R 31/086 (2013.01) [G01R 31/088 (2013.01); G01R 31/52 (2020.01)] 20 Claims
OG exemplary drawing
 
1. A system for protecting an electric power generation installation in an electric power delivery system, comprising:
a protective device in electrical communication with a generator of the electric power generation installation, comprising:
a voltage sensor component to obtain a voltage signal corresponding with a voltage of the first generator of the electric power generation installation;
a current sensor component to quantify a measured current;
a processor; and
a computer-readable storage medium in communication with the processor, the voltage sensor component, and the current sensor component, comprising instructions that when operated cause the processor to:
calculate a pre-fault standing error current using a measured current and a measured reference positive-sequence voltage;
store the standing error reference on the computer-readable storage medium;
detect a ground fault using voltage signals from the voltage sensor component;
calculate an operating current by calculating a difference between the measured current and the pre-fault standing error current;
determine a direction to the ground fault based on the difference between the measured current and the pre-fault standing error current; and
implement a protective action based on the direction to the ground fault.