Dielectric Loss Factor Measurement in Power Systems Based on Sampling Sequence Reconstruction Approach

Abstract

Dielectric loss factor (DLF) is an important parameter to reflect the insulation condition of a high voltage capacitive equipment, which is widely installed in power systems. Hence, the accuracy of DLF measurement will directly affect the safety and stability of the power grid. This paper proposed a new algorithm based on sampling sequence reconstruction approach to accurately measure the DLF without being affected by asynchronous sampling and noise. The proposed method first estimates the fundamental frequency of power grid through the operational processing of voltage or current sampling sequence by weighted iteration with the composite trapezoidal rule. And then, the equivalent synchronous sampling sequences of the voltage and current in one cycle are constructed by using the estimated frequency and original sampling sequences through cubic spline interpolation. Finally, the fast Fourier transform results of the equivalent sequences are applied to obtain the value of the DLF. Simulations and experimental results show the effectiveness and practicability of the proposed method.