Some early busbar protection configurations applied a low impedance differential system that has a relatively long operation time, of up to 0. Current Differential Protection: This protection method connects CT secondaries in parallel and. The protection arrangement for an electrical system should cover the whole system against all possible faults. But. This technical article discusses criteria and requirements for designing protection systems for busbars in HV/EHV networks. ” The only variation is how this is implemented. Which Bus Protection Scheme do you.