The Method of Faulted Section Estimation for Combined Overhead and Cable Power Lines Using Double-Ended Measurements

The article proposes a new method for autoreclosing of combined overhead and cable power lines (OCPL) based on traveling wave methods, which allows to increase the reliability of their protection. Determination of the faulted section is based on the estimation of the level of transient signals. This indicates the simplicity of the method and reduced requirements for the corresponding digital processing algorithms. It is shown that the fault-induced transient during propagation to the line terminals attenuate in a different way depending on the faulted section of the OCPL. The ratio of the signal values at the two ends of the OCPL allows to determine the faulted section with high selectivity. To estimate the method, faults on the OCPL were simulated in PSCAD. The distortions introduced by the line discontinuity, substation equipment and secondary circuits of the measuring transformers were taken into account. The simulation results showed that the faulted section is determined correctly in most cases of faults on the OCPL The exception is short circuits in the overhead section within a small zone near the overhead-cable transition. In these overhead areas, which is several tens or hundreds of meters, the autoreclosing must be blocked.