Harmonic Phasor Estimation Based on Frequency-Domain Sampling Theorem

Harmonic phasor estimation can be used both in power system protection and monitoring applications, such as islanding detection, high-impedance fault location, and harmonic state estimation. A key challenge for harmonic phasor estimation is that different harmonics have different harmonic frequency bandwidths. As a result, a harmonic phasor estimator (HPE) that can adapt to such variations is needed. Although the sinc interpolation function-based estimator (SIFE) has such ability, it has disadvantages that: 1) it needs numerous simulations to select the model parameter and 2) it cannot obtain zero-error results under nominal frequency condition. In this article, a novel HPE is proposed based on the frequency-domain sampling theorem, where the harmonic phasor is modeled based on several imaginary exponential functions. The proposed HPE is compared with the SIFE in frequency response, model parameter selection scheme, and simulation tests. The results show that the proposed HPE has the following three advantages: 1) it has an easier scheme for model parameter selection; 2) it has zero-error results under nominal frequency condition; and 3) it has higher accuracy under harmonic frequency deviation and harmonic modulation conditions.