Security Logic For Subsequent Out-Of-Step (Os) Condition; Without Programmable Contact Option; Oscillographic Data - ABB REL300 Instruction Manual

I.L. 40-385.7
The following quantities are used for the blinder sensing:
where
Operation occurs if the operating voltage leads the polarizing voltage. The characteristics are
as shown in Figure 3-18b.
Both inner and outer blinders are included in phases A and B for OSB detection on the SPT
application. Blinder reaches are determined by the setting of RT and RU, respectively.
3.4.17.1 Security Logic for Subsequent Out-of-Step (
Model power system tests, when using a motor-generator-set, show that the Zone 1 impedance
unit may overreach or respond to a reversed fault. This was attributable to motor-generator set
instability following delayed clearing on an external fault. In this case, following a delayed
clearing of external faults, the relay system action is dependent of the location of the
electrical center. The Zone 1 relay will operate and trip if the electrical center is within
the Zone 1 reach. The conventional OSB logic can not distinguish this condition be-
cause it looks like a fault to the relay.
Logic was added utilizing the inner blinder and Zone 1 sensing sequence, plus a 50 ms timing
action (as shown in Figure 3-18a), AND-131A, AND-131B, AND-131C and OR-122A, to differ-
entiate between a fault and a subsequent out-of-step condition. A subsequent OS condition
is identified if the inner blinder operates 50 ms ahead of the Zone 1 3φ unit. This logic will
not affect normal Zone 1 trip time, nor will it affect normal out-of-step blocking.
3.4.18 Optional Single-Pole-Trip (SPT) Logic and Outputs Without Programmable Contact Option
• (Figure 3-20)
• Consult Factory

3.4.19 Oscillographic Data

The oscillographic data has 8 samples per cycle, 1 cycle pre-trigger and 7 cycles post-trigger.
It includes 16 events and 24 digital intermediate targets (test points). The data can be accessed
via the communication port.
3-14
Blinder
Polarizing
Line
-j(V XG + I X R C ∠(PANG–90
Left
j(V XG - I X R C ∠ (PANG–90
Right
VXG = Phase to ground voltage, V A G or V BG
Phase current in φA or φB
I =
X
R = Setting of the unit (RT or RU). RT for inner blinder (21BI), RU for out-
C
er blinder (21BO)
PANG = The positive sequence line impedance angle
Operating
°
∠(PANG–90
) I
X
°
∠(PANG–90
) I
X
OS
) Condition
°
)
°
)