A new interharmonics detection method based on spectrum leakage

With the widely application of a great quantity of nonlinear electrical components, harmonie and interharmonic components in power system have become a complicated problem. In the power system, there is fundamental wave, harmonics and interharmonics. The Fast Fourier Transform method can make the precise detection and analysis of integer harmonies come true, which based on simple transformation of FFT. In order to accurate detect interharmonics people must eliminate the interference between harmonie and fundamental. Their characteristic help us to distinguish them. In order to improve computing speed, three point method combine FFT Because of these improvement ,people can calculate interharmonics accuracy.

I. Introduction

With the extensive use of a great quantity of power electronic devices and nonlinear components, harmonic pollution in power system has become a serious and complicated problem. The pollution is not only in harmonics, but also inter-harmonics [1] [2]. Harmonics can make the electrical component in unsafety state [3]. Operator can not clearly distinguish the device's signal because of lamps flicker phenomenon. Relay will move in error time [4]. Therefore, it is essential to detect the inter-harmonics precisely in order to become a foundation for the management of the interharmonics.