State prediction of electronic voltage transformer based on Q-ARMA

As an ideal substitute for traditional electronmagnetic transformers, electronic voltage transformers are widely used in smart grids. Its problem at present is the poor long-term stability of the error, which has caused some hidden danger to the safety, stability and economic of the power grid. The regular off-line calibration method is not conducive to the timely detection of the error state for electronic voltage transformer. A method of error state prediction based on Q -ARMA is proposed in this article. The measurement data of the three-phase electronic voltage transformer are collected, and the error state of the electronic voltage transformer is mapped to the Q statistic under the constraints of the electrical physical relationship by using the principal component analysis method. The influence of grid fluctuation on the prediction of error states is eliminated by this method. The ARMA prediction model of Q statistics is established, and the experiments show that this method can accurately predict the trend of the error state of electronic voltage transformer.