Settings Examples - ABB RELION 650 Series Applications Manual

Section 6
Differential protection
CurveType
This is the setting of type of delay for low differential currents.
tMinInv
This setting limits the shortest delay when inverse time delay is used. Operation faster than
the set value of
If the user-programmable curve is chosen the characteristic of the curve is defined by
equation 16.
= ×
t k
op
EQUATION1418 V1 EN-US
where:
t
op
k
a, b, c, p are settings that will model the inverse time characteristic
6.2.3.6

Settings examples

Setting example for line with power transformer in the protected zone
In this section it is described how setting parameters can be chosen for a line with a power
transformer in the protected zone. The line is shown in Figure 46, and the circuit impedances
are shown in Figure 47. The protection zone is limited by the current transformers CT1, CT2
and CT3. The terminals are situated in two separate substations, Substation 1 and Substation
2. The circuit is protected by two protection terminals, Protection Terminal 1, and Protection
Terminal 2. Except for a minor distortion of data due to the communication between the two
protection terminals, the protection terminals process the same data. Both protection
terminals are masters. If at least one of them signalizes an internal fault, the protected circuit
is disconnected. Settings of Protection Terminal 1 and Protection Terminal 2 must be equal,
except for a few parameters, which can be pointed out.
90
tMinInv is prevented.
æ
ç
ç
a
ç
p
æ ö
I
ç
Measured
-
c
ç ÷
ç
è ø
è IMaxAddDelay
is operate time
is time multiplier of the inverse time curve
ö
÷
÷
+
b
÷
÷
÷
ø
1MRK 505 363-UEN A
M12541-321 v3
M12541-324 v4
(Equation 16)
M12541-349 v3
M12941-3 v7
Application manual