Research on Protection Tripping Scheme of Multiple Criteria with High Reliability for HV Transmission Lines

The abnormities occurring at any part of sampling process may cause the maloperation of dual-configured protection systems in smart substations. To cope with this problem, multiple differential protection criteria are formed, which use the currents acquired from the lines that connect to the busbars connecting to the double ends of the protected line. All the acquired information is shared in the substation area protection platform. Then, a novel protection tripping scheme of multiple criteria for high voltage (HV) transmission line is proposed. Theoretical analysis and simulation results indicate that compared with the existing 1-out-of-2 tripping scheme, the proposed protection tripping scheme is immune to the abnormities of current transformer (CT) such as saturation, interference and disconnection, which can effectively enhance the reliability of line protection.