Page 226 - Practical Power System and Protective Relays Commissioning
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226 Practical Power System and Protective Relays Commissioning
FIGURE 18.6.26 Blocking overreach transfer scheme.
At end A, fault F 1 will be seen by Z 2 A if a received blocking signal is
received from remote end B. This means the relay will not trip on F 1 , but
if the fault is on the line side as F 2 no signal will be received from end B
to block operation of relay at end A, then the relay at end A Zone 2 will
trip instantaneously for fault F 2 (refer to Fig. 18.6.27 for the scheme trip
logic).
FIGURE 18.6.27 permissive overreach transfer trip blocking scheme.
18.6.6 DISTANCE RELAY INPUTS FOR CORRECT
MEASUREMENT OF DIFFERENT TYPES OF FAULTS
The distance relay to measure the correct value of impedance should have
the correct inputs as follows:
