Phase and ground protection using tilt-limited adaptive quadrilateral characteristic

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 phase comparator to define a quadrilateral characteristic comprising an adaptive reactance element and an adaptive resistance blinder;
• a tilt-limiting module to define a polarizing quantity used by the phase comparator, as:
• a polarizing current quantity when an angle between the polarizing current quantity and a corresponding loop current quantity does not exceed a predetermined threshold;
• and,
• a self-polarizing quantity when the angle exceeds the predetermined angle and
• wherein the quadrilateral distance module is configured to detect the fault in the electrical power system using the quadrilateral characteristic and stimulus obtained from the electrical power system.

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 define a polarizing quantity used by the phase comparator as a polarizing current quantity when an angle between the polarizing current quantity and a corresponding loop current quantity does not exceed a predetermined threshold, and to disable 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.