A new method for interharmonic detection based on harmonic filtration

A crucial problem for improving interharmonic detection precision is how to reduce the influence from harmonic spectral leakage. This paper analyzes the character of the power system´s spectral leakage, and puts forward a new interharmonic detection method. First, measures harmonic component with windows and interpolated FFT, then, filters away the harmonic component from the original signal, last, uses FFT to analyze the sample signal with fixed sampling frequency and gets the interharmonic component without harmonic spectral leakage interference. The example shows that, compare to the traditional detection method, this method does not need synchronization procession. So it has such advantages as smaller calculation amount, higher detection precision, it can be used in the field of interharmonic´s real-time detection.