Improvement to correlation algorithm for dielectric dissipation factor calculation of capacitance equipments

Because it was unable to integrate in a full period, a remarkable error would appear in the calculation of dielectric dissipation factors of capacitance equipments by traditional finite time discrete correlation algorithm when the sampling frequency was not synchronous with power network signal's frequency. The authors calibrated the integration interval by linear interpolation, used the trapezoidal integration to replace the rectangular integration and applied the optimal sampling frequency and sample size to improve calculation accuracy. The simulation shows that the calibrated correlation function method possesses stronger inhibition capability and can significantly reduce the calculation error of dielectric dissipation factor, thereby, the synchronous sampling card is no more needed. In addition, the sampling frequency of the proposed method is not high as well as the sample size is not large, so it is easy to implement for the proposed method by the measuring system based on micro-controller unit (MCU) or digital signal processor (DSP).