This technical article discusses criteria and requirements for designing protection systems for busbars in HV/EHV networks. Current Differential Protection: This protection method connects CT secondaries in parallel and. Busbars in power systems are the location where transmission lines, generation sources, and distribution loads converge. Because of this convergence, short circuits located on or near the busbar tend to have very high magnitude currents. This requirement is further emphasized. A busbar is a strip or bar of copper, brass or aluminum that conducts electricity within a switchboard, a substation or a battery bank. Its purpose is to conduct a substantial current of electricity. ABB's busbar protection is designed for phase-segregated short-circuit protection, control, and.