US 12,418,168 B2 · High-impedance differential protection using a diversity of signals

Abstract

A system for high-impedance differential protection for power systems using a variety of signals from the power system. A fault may be detected using filtered phase current or filtered phase voltage magnitudes from current transformers (CTs) connected in parallel by phase. A fault may be detected using filtered phase voltages and raw phase voltages from the CTs. A fault may be detected using raw phase currents and raw phase voltages from the CTs. A fault may be detected using filtered phase currents and raw phase currents. A fault may be detected using raw phase currents and raw neutral currents. The embodiments herein maintain dependability and security of a differential element even when low-class CTs are used. The embodiments herein may allow users to optimize pickup settings even when low-class CTs are used.

Claims20

Dependent claims

A protective device for use in an electric power system, the protective device comprising:

a first input configured to receive a first signal from a transformer in electrical communication with a first portion of the electric power system, and to generate a first raw signal representative of a first electrical condition in the first portion of the electric power system;
a second input configured to receive a second signal from a second transformer in electrical communication with a second portion of the electric power system, and to generate a second raw signal representative of a second electrical condition in the second portion of the electric power system;
and
a logic subsystem configured to:
compare the first raw signal to a first threshold;
compare the second raw signal to a second threshold;
generate a count representing samples when the first raw signal is outside the first threshold and when the second raw signal is outside the second threshold;
and
generate a protective action signal based on the count.

6 more elements

Dependencies are inferred from the claim text.

High-impedance differential protection using a diversity of signals

Life of this patent

High-impedance differential protection using a diversity of signals

Life of this patent

Abstract

Claims20