Fast-individual-harmonic-extraction technique

Harmonic distortion in power networks is continuously increasing owing to the increased use of nonlinear loads in power-distribution networks. Consequently, harmonic monitoring and control are becoming particularly important for both utilities and consumers to reduce their harmful effects. In some applications, such as real-time harmonic monitoring and active filters, techniques for fast extraction of individual harmonic components are required. The relatively long response time of conventional techniques make them less appealing when the speed of response is important. The paper deals with the problem of individual-harmonic extraction for the purpose of harmonic filtering and compensation. A common problem associated with existing individual-harmonic-extraction techniques is the speed of extracting a single harmonic component, which determines the response of the compensator. Standard harmonic-extraction techniques are investigated and a new fast-individual-harmonic-extraction (FIHE) technique is proposed. It is shown that the proposed FIHE is capable of performing harmonic extraction six times faster than the Fourier transform and provides better filtering characteristics than traditional filters such as Butterworth and FIR filters. Computer simulation and laboratory experimental results are provided to illustrate the characteristics and performance of the proposed technique.