Page 269 - Practical Power System and Protective Relays Commissioning
P. 269
Protection Relays Chapter | 18 265
Radio links;
Few used in the past;
Optical fibers.
The most recent system is to transfer the current signals and all tripping
and protection accelerating signals along of fiber optic between the two ends
of the line. Refer Fig. 18.10.8.
FIGURE 18.10.8 Line differential protection with a fiber-optic communication channel.
In recent relays there are two bias constant zones in its operating
characteristic, the first one for low fault currents that need less bias and
the second one for high fault currents that need more bias as shown in
Fig. 18.10.9.
FIGURE 18.10.9 Stabilization characteristic of fiber-optic line differential protection.
