Phase and ground protection using tilt-limited adaptive quadrilateral characteristic
View Patent ↗A quadrilateral distance module may be used to detect faults in an electrical power system. A resistive coverage of the quadrilateral distance module may be defined by an adaptive resistance blinder. Tilt of the adaptive reactance element and resistance blinders may be limited. When an angle between the sequence-component based, current polarizing quantity and the element loop current does not exceed a predetermined angle threshold, the sequence-component based polarizing quantity may be used. Otherwise, the element loop current may be used to limit the tilt. Fault detection may comprise comparing both the adaptive resistance blinders for forward and reverse load flow conditions to power system stimulus and detecting a fault when the stimulus satisfy either blinder.
1. An apparatus to protect an electrical power system comprising:
a quadrilateral distance module configured to detect a fault in an electric power system using a quadrilateral characteristic, the quadrilateral distance module comprising:
a tilt-limiting module configured to:
receive a current polarizing quantity and a loop current quantity,
calculate an angle between the current polarizing quantity and the loop current quantity, and
compare the angle between the current polarizing quantity and the loop current quantity with a predetermined threshold; and,
a phase comparator module configured to:
when the angle does not exceed the predetermined threshold, detect a fault in the electrical power system using the current polarizing quantity and an operating quantity and,
when the angle exceeds the predetermined threshold, detect a fault in the electrical power system using the loop current quantity and an operating quantity;
wherein the quadrilateral distance module is further configured to receive a stimulus from the electrical power system and to compare the stimulus to the quadrilateral characteristic to detect the fault.
2. The apparatus of claim 1 , wherein the current polarizing quantity comprises at least one of a negative-sequence current polarizing quantity, a positive-sequence current polarizing quantity, a zero-sequence current polarizing quantity, and a sum of positive-sequence and zero-sequence current polarizing quantities.
3. The apparatus of claim 1 , wherein the loop current quantity comprises at least one of a phase-to-phase loop current and a phase-to-ground loop current.
4. The apparatus of claim 1 , wherein the phase comparator module comprises a reactance module.
5. The apparatus of claim 1 , wherein the phase comparator module comprises a resistance module.
6. The apparatus of claim 1 , wherein:
the quadrilateral characteristic comprises a reactance element; and,
the current polarizing quantity comprises a negative-sequence current polarizing quantity.
7. The apparatus of claim 6 , wherein the loop current quantity comprises a phase-to-phase loop current.
8. The apparatus of claim 1 , wherein:
the quadrilateral characteristic comprises a resistance blinder; and,
the current polarizing quantity comprises a positive-sequence current polarizing quantity.
9. The apparatus of claim 8 , wherein the loop current quantity comprises a phase-to-phase loop current.
10. The apparatus of claim 1 , wherein:
the quadrilateral characteristic comprises a resistance blinder; and,
the current polarizing quantity comprises a negative-sequence current polarizing quantity.
11. The apparatus of claim 10 , wherein the loop current quantity comprises a phase-to-phase loop current.
12. The apparatus of claim 1 , wherein:
the quadrilateral characteristic comprises a reactance element; and,
the current polarizing quantity comprises a zero-sequence current polarizing quantity.
13. The apparatus of claim 12 , wherein the loop current quantity comprises a phase-to-ground loop current.
14. The apparatus of claim 1 , wherein:
the quadrilateral characteristic comprises a reactance element; and,
the current polarizing quantity comprises a negative-sequence current polarizing quantity.
15. The apparatus of claim 14 , wherein the loop current quantity comprises a phase-to-ground loop current.
16. The apparatus of claim 1 , wherein:
the quadrilateral characteristic comprises a resistance blinder; and,
the current polarizing quantity comprises a zero-sequence current polarizing quantity.
17. The apparatus of claim 16 , wherein the loop current quantity comprises a phase-to-ground loop current.
18. The apparatus of claim 1 , wherein:
the quadrilateral characteristic comprises a resistance blinder; and,
the current polarizing quantity comprises a negative-sequence current polarizing quantity.
19. The apparatus of claim 18 , wherein the loop current quantity comprises a phase-to-ground loop current.
20. The apparatus of claim 1 , wherein:
the quadrilateral characteristic comprises a resistance blinder; and,
the current polarizing quantity comprises a composite of a positive-sequence and a zero-sequence current polarizing quantity.
21. The apparatus of claim 20 , wherein the loop current quantity comprises a phase-to-ground loop current.
22. The apparatus of claim 1 , wherein:
the quadrilateral characteristic comprises a resistance blinder; and,
the current polarizing quantity comprises a composite of a positive-sequence and a negative-sequence current polarizing quantity.
23. The apparatus of claim 22 , wherein the loop current quantity comprises a phase-to-ground loop current.
24. An apparatus to protect an electric power system, comprising:
a phase quadrilateral distance module configured to detect a fault in an electric power system using a quadrilateral characteristic, the phase quadrilateral distance module comprising:
a phase comparator to define an adaptive quadrilateral element comprising an adaptive reactance element and an adaptive resistance blinder; and,
a tilt-limiting module to limit an adaptive tilt of at least one component of the quadrilateral element by:
defining a polarizing quantity used by the phase comparator as a polarizing current quantity only when an angle between the polarizing current quantity and a corresponding loop current quantity does not exceed a predetermined threshold, and
disabling the phase comparator when the angle is greater than the predetermined threshold;
wherein the quadrilateral distance module is configured to detect the fault in the electrical power system by comparing the quadrilateral characteristic and a stimulus obtained from the electrical power system.
25. The apparatus of claim 24 , wherein the phase comparator comprises a reactance element and the corresponding loop current comprises a phase-to-phase loop current.
26. The apparatus of claim 24 , wherein the phase comparator comprises a resistance blinder and the corresponding loop current comprises a phase-to-phase loop current.
27. The apparatus of claim 24 , wherein the phase comparator comprises a reactance blinder and the corresponding loop current comprises a phase-to-ground loop current.
28. The apparatus of claim 24 , wherein the phase comparator comprises a resistance blinder and the corresponding loop current comprises a phase-to-ground loop current.