Circuit Breaker Failure to Operate or Maloperation: Check the energy storage mechanism, closing/tripping coils, auxiliary switches, and secondary circuits. High-Voltage Fuse Blown: Measure voltage across the fuse terminals; inspect busbar joints, cable terminations, and. GE Multilin provides protective relays that support all busbar protection techniques, including overcurrent, high-impedance differential, and percentage (low-impedance) differential. GE Multilin. Busbar protection (BBP): Protection intended to detect and operate to clear faults on a busbar. ect the busbar systems for lower voltage levels (10 kV, 13 kV, and 21 kV).