This scheme may be a preferred choice, however, when
one of the protection zones in Fig. 6 is a bus. Assume the
Zone 1 IED is a low-impedance bus relay measuring all
individual bus currents and the bus is reconfigurable, calling
for dynamic routing of the BFT signals. In this case, the BFT
signals are naturally routed by the bus relay using the same
input information and logic as for the main bus trips..