Typically, distance relays protect transmission lines from power system faults by using the method of step distance protection. This method uses the line impedance as the basis to form zones of protection and each zone is calculated by a predetermined percentage of the. tion of Protection System Performance During Faults. T ve. Distance relays measure impedance (Z = V/I) to detect faults. The IEC standard for relay coordination provides clear guidelines and methodologies to ensure that protective relays work in harmony to isolate only the faulty section of the system while keeping the rest. This technical report refers to the electrical protections of all 132kV switchgear. All calculations are based on the available documentation/ information. These settings may be revaluated during the commissioning, according to actual and/or measured values. Protection selectivity is partly. A particular focus will be on the Switch-On-to-Fault (SOTF) feature, a critical function designed to prevent severe network disturbances during specific fault conditions.
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