Verification and Implementation of Pseudo-Random-Binary-Sequences for Online Determination of Grid Impedance Spectrum

The number of inverter based distributed power generators connected to the power network has rapidly grown in recent years. The consequence of this phenomenon is an increasingly complex distribution grid, requiring advanced and intelligent monitoring and observation tools in order to guarantee satisfactory power quality and reliability. This paper describes a novel power line impedance estimation method, implementing an innovative technique based on modifications of the Pulse Width Modulator’s pulse pattern on the inverters, in order to generate Pseudo-Random Binary Sequence based pilot signals. The stimuli are generated at different locations in the distribution grid, and detected at the transformer sub-station through cross correlation between the received distorted signal and the sequence, the parameters of the propagation channel can be estimated. Simulations in typical grid situations verify that the proposed algorithm is robust to a realistic environment and woul