High-Order SOGI-Based Observation Technology of Leakage Electrical Impedance

Aiming at the problem that the leakage impedance measurement results are easily affected by the harmonics of the power grid, a leakage current and leakage impedance observation technology based on a high-order generalized second-order integrator (SOGI) is proposed in this paper. The high-order SOGI observer is designed to observe the amplitude, phase angle and frequency information of the grid voltage and the leakage current, effectively filter out the influence of harmonics, and then the leakage loop impedance can be calculated by the instantaneous amplitude, phase angle of the voltage and leakage current. Finally, it is verified by simulation that the proposed leakage impedance estimation technology is of high accuracy and strong anti-harmonic ability.