ABB RELION Series Technical Manual page 474

Section 5
Protection related functions
468
GUID-61D73737-798D-4BA3-9CF2-56D57719B03D V4 EN
Figure 239: Start logic
Timer 1
Once activated, the timer runs until the set Retrip time value has elapsed. The time
characteristic is according to DT. When the operation timer has reached the value set
with Retrip time, the retrip logic is activated. A typical setting is 0...50 ms.
Timer 2
Once activated, the timer runs until the set CB failure delay value has elapsed. The
time characteristic is according to DT. When the operation timer has reached the set
maximum time value CB failure delay, the backup trip logic is activated. The value of
this setting is made as low as possible at the same time as any unwanted operation is
avoided. A typical setting is 90 - 150 ms, which is also dependent on the retrip timer.
The minimum time delay for the CB failure delay can be estimated as:
CBfailuredelay Retriptime t
≥
A070693 V3 EN
t maximum opening time for the circuit breaker
cbopen
t maximum time for the breaker failure protection to detect the correct breaker function (the
BFP_reset
current criteria reset)
t safety margin
margin
t t
+ + +
cbopen BFP reset _ margin
1MRS758755 A
(Equation 44)
REC615 and RER615
Technical Manual