A Resolution-Enhanced Sliding Matrix Pencil Method for Evaluation of Harmonics Distortion in Shipboard Microgrids

Abstract

Due to the rapid adoption of power electronics technology in shipboard microgrids (SMGs) in recent years, harmonic contamination has become now a crucial topic for these power systems. In order to sustain the safety of the electrical power systems, standards for power quality have imposed strict limits on the harmonic distortion allowed. In these standards, the application of the fast Fourier transform (FFT) with a window size of 10/12 cycles is often recommended for the harmonic evaluation. This method is not practical for SMGs due to large variations in load and frequency in a short duration. To address this issue, this article proposes a signal periodicity-independent algorithm to estimate the current harmonic distortion of SMGs by solving an eigenvalue problem with a short transient response. The proposed algorithm, which is based on a resolution-enhanced sliding matrix pencil method (SMPM), is distinguished by its frequency independency feature, and as a result of this, feature system frequency variations and the existence of interharmonics do not affect its accuracy. The evaluation of the proposed method is carried out under the MATLAB software and is experimentally verified via analyzing the electrical power system current of a container ship.