Development of leakage energy allocation approach for time-varying interharmonics tracking

Recently, an increasing use of power electronic facilities in industry has produced considerable harmonics and interharmonics in power systems. The power supply quality is therefore seriously threatened. The discrete Fourier transform (DFT) is currently the most important tool in signal analysis. However, a misapplication of DFT may result in incorrect outcome because of some inherent limitations such as spectral leakage or aliasing effect etc. The existing interharmonics even raise more difficulty in signal analysis than harmonics. To overcome this dilemma, this study develops a strategy of leakage energy allocation method for both stationary and non-stationary interharmonics identification. The proposed algorithm can regain its original interharmonics amplitude by restoring all spilled leakage energy, and also finds its individual frequency component according to the distribution of spilled leakage energy. The performance effectiveness of the proposed approach is verified using the numerical examples in terms of reliability, rapid response and high-precision performance.