The invention provides a high-precision
electric energy metering and fault diagnosis method adaptive to multiple working conditions, and the method comprises the following steps: carrying out the multi-rate synchronous sampling of an
electric parameter through a double-AD parallel sampling architecture, collecting a fundamental wave
voltage / current
signal through a low-speed AD module at a sampling rate of 4kHz, capturing a high-frequency
harmonic wave and a
transient signal through a high-speed AD module at a sampling rate of 256kHz, and carrying out the fault diagnosis of the high-frequency
harmonic wave and the
transient signal; a sampling mode is dynamically switched according to the load
harmonic content; a sliding window mechanism is adopted to carry out multiple times of repeated detection on the same
electric parameter, five times of independent measurement are completed in a 200ms time window, an
outlier is eliminated based on a Pauta criterion, then a weighted mean value of a
signal-to-
noise ratio is calculated, AD reference
voltage is calibrated in real time through a PT100 temperature sensor, and the accuracy of the AD reference
voltage is improved. Carrying out nonlinear dynamic compensation by combining a cubic spline interpolation method of a pre-stored load characteristic curve; and constructing a composite
electric energy calculation model, summing the fundamental wave
electric energy and the harmonic electric energy weighted according to the standard to generate a total electric energy value, and comparing a metering result with a theoretical value in real time by using a digital phase-locked loop.