An oscilloscope method for eliminating the interference and disturbance voltages for the earthing measurements of large earthing systems in substations

Enhanced grounding system impedance measurements for high-voltage substations

“…The underlying idea of TM is based on recording the transient state caused by switching‐on the test circuit . In the TM, a 50‐Hz current injection system consisting of a power transformer commanded from the substation control room was used.…”

“…In order to improve the susceptibility to the power frequency interference and its harmonics in the measurements of grounding system impedance of high‐voltage substation, we propose the shifted frequency method (SFM). The accuracy of proposed SFM will be compared with the corresponding results obtained by the transition method (TM) as well as by the heavy‐current injection method (HCM) . The measurement will be conducted at two substations.…”