초록 ▼

A method and system for detecting the peak of respective half-cycles of a sinusoidal waveform. The sinusoidal waveform is rectified and only sample points above a first threshold are analyzed. The peaks of each half-cycle are only accepted if they are above a second, greater threshold. Peaks below t

A method and system for detecting the peak of respective half-cycles of a sinusoidal waveform. The sinusoidal waveform is rectified and only sample points above a first threshold are analyzed. The peaks of each half-cycle are only accepted if they are above a second, greater threshold. Peaks below the second threshold are not accepted. The peaks themselves are detected by starting a counter at the first sample in the rectified waveform which is above the first threshold value. Once the rectified waveform descends below the first threshold, the counter is stopped and the maximum value of the previous k samples is the peak value, where k is the counter value for the successive samples above the first threshold. The peak value so determined is rejected if it is less than the second threshold value. On the other hand, when the peak value is above the second threshold, it is averaged with the last valid peak value (above the second threshold). Thus, the V/Hz value remains the same until a new, valid peak is determined. A preferred embodiment implements such a digital peak detector in a digital relay system for detecting overexcitation of a power system.

대표청구항 ▼

[ What we claim is:] [1.] A method of detecting a peak in a sinusoidal digital signal, comprising the steps of:establishing a first threshold which is a first predetermined percentage of the magnitude of the sinusoidal digital signal;establishing a second threshold which is a second predetermined pe

[ What we claim is:] [1.] A method of detecting a peak in a sinusoidal digital signal, comprising the steps of:establishing a first threshold which is a first predetermined percentage of the magnitude of the sinusoidal digital signal;establishing a second threshold which is a second predetermined percentage of the magnitude of the sinusoidal digital signal, the second threshold being greater than said first threshold;counting each successive sample in a half-cycle of the sinusoidal digital signal having a magnitude above said first threshold;determining which sample k counted in said counting step had the greatest magnitude, where k is the value for successive samples above the first threshold;comparing a magnitude of sample k to said second threshold; andrejecting said compared sample k as the peak of the sinusoidal digital signal if the magnitude of said sample k is less than said second threshold.