Electric Power Research Institute Incorporated

Richard J Murphy

Robert A Lacy

Delano D Wilson

Jonathan B Wright

James J Burke

Dale A Douglass

Glenn D Baker

A circuit samples and stores high frequency transient events that affect low frequency steady state signals. The circuit digitizes the high frequency transient signal and samples the digital signals. The present and previously stored data samples are compared, and if the difference exceeds a threshold, the present sample is stored in memory, if the memory is not full, and simultaneously the internal counter is reset. If a number of successive samples do not exceed the threshold and are not stored within a defined interval, the last sample of the interval is stored and an interval counter is reset to zero. A logic circuit controls the timing and operation of the counter and storage of the sampled data.

Circuit for high-frequency sampling and compression of data for

A selected point in an electric power system is monitored for subsequent fault analysis. The voltage and current at the point is continuously sampled with samples for a predetermined period of time being temporarily stored in memory. In response to a Fault Event, voltage and current samples at differing sample rates and for differing periods of time are recorded. Voltage and current samples after a Cold Load Pickup are recorded, also the recorded samples allow later analysis of the fault and identification of the cause of the fault.

Method and means for monitoring faults in an electric power system and

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Clifton Park, NY, United States of America

Richard J Murphy