An Interharmonics Traceability Method Based on Thermal Converters

Product safety is essential for the power grid. However, the application of nonlinear power electronic equipment could cause safety problems in the power grid. The application of nonlinear power electronic equipment in the field of wind energy have led to continuous interharmonics in the power grid. The traditional harmonic analysis method is based on the Fourier transform. Nevertheless, the Fourier transform method could cause obvious spectral leakage and fence effects, resulting in large errors in the analysis results. To solve the problem that traditional methods cannot accurately trace the interharmonic signal to DC voltage, a traceability method of the interharmonic signal based on thermal converters is proposed. A traceability device of the interharmonic signal based on thermal converters is developed. With the novel device, the interharmonic signal is converted into thermal signal. Then the thermal signal is converted into electrical signal. The total effective value of the interharmonics signal is obtained by equivalent calculating. Finally, the interharmonics signal is traced to DC voltage. The results show that the present method can accurately trace the interharmonic signal. This novel method is useful for improving product safety in the power grid.