GRID IMPEDANCE ESTIMATION BASED ON TOTAL LEAST SQUARES

摘要

A method for estimating an equivalent impedance of an electrical grid (10) comprises: receiving a plurality of measurement values of a grid voltage $\left({\mathit{V}}_{\mathit{pcc}}^{\mathit{ti}}\right)\mathop{\mathrm{image}}$ and a grid current $\left({\mathit{I}}_{\mathit{pcc}}^{\mathit{ti}}\right),\mathop{\mathrm{image}}$ measured over a time interval at different time points; minimizing an objective function (S) based on the measurement values $\left({\mathit{V}}_{\mathit{pcc}}^{\mathit{ti}},{\mathit{I}}_{\mathit{pcc}}^{\mathit{ti}}\right),\mathop{\mathrm{image}}$ a grid voltage parameter (X̃₀), and parameters (X̃₁) of the equivalent impedance, which objective function (S) comprises a length of an error vector (ε); and determining the equivalent impedance (X₁) by dividing the parameters of the equivalent impedance (X̃₁) by the grid voltage parameter (X̃₀). The error vector (ε) is composed of a grid voltage based vector (VX̃₀) based on grid voltage measurements $\left({\mathit{V}}_{\mathit{pcc}}^{\mathit{ti}}\right)\mathop{\mathrm{image}}$ times the grid voltage parameter (X̃₀) and a grid current based vector (A₁X̃₁) based on grid current measurements $\left({\mathit{I}}_{\mathit{pcc}}^{\mathit{ti}}\right)\mathop{\mathrm{image}}$ times the parameters (X̃₁) of the equivalent impedance.