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

Abstract

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.

Development of interharmonics identification using enhanced‐FFT algorithm

“…The proposed e‐FFT model is based on the FFT for suiting interharmonics measurement. According to the FFT analysis, the relationship between harmonic frequency and dispersed energy can be classified into two cases: small and big frequency deviation [23]. Case 1: Depiction for small frequency deviation is shown in Fig.…”

“…Relation between harmonic frequency and dispersed energy [23] a Small frequency deviation b Big frequency deviation…”

Bearing vibration detection and analysis using enhanced fast Fourier transform algorithm

“…From the above principle, a mathematical model can be deduced from the relation between the frequency deviation amount and dispersed energy distribution. 35 It concludes that the real frequency can be represented by the dominant frequency (f k ) plus ''frequency deviation'' (Df k ), that is, f k +Df k .…”

Identification of interharmonics using disperse energy distribution algorithm for flicker troubleshooting

“…The orthogonal vector of the proposed model may not be convinced without effectively convergent mechanism [19]. Although a number of approaches focused on the measurement of interharmonics are still being undergoing in recent years, it is still a big challenge for those that are close to the fundamental or harmonics related to significant flicker problems [20–23].…”