Rockwell Automation Technologies Incorporated

Ronald N Jansen

Steven T Haensgen

William Howell Martin

Ricky A Hurley

A system and method for detecting a fault condition by a relay is provided. The system includes means for detecting phase currents through three electrical phases, means for detecting a ground fault current, a processor configured to perform a current-based function based upon at least one of the phase currents and a filter. The processor is configured to perform current-based functions based on whether the filter is enabled or disabled.

System and method for detecting a fault condition

A technique for computing RMS values for sampled waveforms. More specifically, a technique for computing RMS values for periodic waveforms, using data taken from a full waveform, a half waveform or some other portion of a waveform is described. Each RMS calculation is based on a different algorithm and provides accurate, real time data.

Method and apparatus for calculating RMS value

A configurable overload relay selectively operable in a single-phase mode of operation and a multi-phase mode of operation is configured to sense current flow through power conductors. The relay is further configured to determine a parameter related to the current flow, such as average current, vector sum of phase currents, and current imbalance, based on selection of either the single-phase or multi-phase mode of operation. Regardless of the selected mode of operation, the relay can provide protection for multiple types of power conductor fault conditions, including ground faults, overloads, and phase loss. The relay further can be configured to provide a reporting signal indicative of the value of the determined current-related parameter and/or the occurrence of the fault condition.

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New Berlin, WI, United States of America

Ronald N Jansen