ABB Relion 670 Series Applications Manual page 237

1MRK 511 401-UEN Rev. K
=
X
SCB
GUID-909A36A1-9430-4EA1-A619-C85AF845332D V1 EN-US
Then, IBase from
IBase
GUID-4FBD6FA9-21FE-43FD-8B91-E8189B107B3F V1 EN-US
This current should be set as
UBase as rated phase-to-phase voltage (that is, UBase = 400 kV).
Set
In order to set the two over-current stages in the cascading failure protection function, enter
the following settings:
Current Input and Voltage Input settings:
Note that the negative sequence measurement must be selected for the current and the
voltage inputs. The base current and voltage shall be set equal to the SCB rated current and
voltage respectively(for example, 289 A, 400 KV).
Stage 1: The default setting of
( 1-117/125).
Note that these settings can be entered for all the SCB applications irrespective of the actual
SCB rating, because all pickup values are related to the global base quantities.
Stage 2: The default setting of
tDef2 is set with the typical value of 0.05 sec to make it a high speed stage.
Note that these settings can be entered for all the SCB applications irrespective of the actual
SCB rating, because it relates all the pickup values to the base quantities given in
10.2 Current unbalance protection of SCB, SCUCPTOC
10.2.1 Identification
Function description
Current unbalance
protection of SCB
10.2.2 Application
A shunt capacitor bank can be used in both transmission and distribution networks, for
example by supporting reactive power flow, reducing line losses, and improving the system
voltage profile.
A capacitor unit (C
capacitor unit is built by arranging a group of individual capacitor elements in series and
Bay control REC670
Application manual
( )
2
400 3
2
U
=
( )
MVar 200 3
Equation 103 is calculated as follows:
´
UBase 400 1000
= =
´ ´
3 X 3 800
SCB
IBase .
I> is 125% IBase , accordingly set VDepFact1 to 0.064
tDef1 is set with the typical value of 0.2 sec.
IEC 61850 identification
SCUCPTOC
) is the basic building block of the capacitor bank as shown in Figure. A
unit
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= W
800
=
289 A
I>> is 130% IBase , accordingly set VDepFact2 to 0.1 ( 1-117/130).
IEC 60617 identification
dI>C
Section 10
Unbalance protection
(Equation 104)
(Equation 105)
Figure 107.
GUID-6B41F976-9393-41E4-82F8-8AD841AC6E63 v1
GUID-235120CF-F959-4092-A275-8511903520E8 v1
ANSI/IEEE C37.2 device
number
60N
GUID-B4390A3D-695D-4D62-BD23-4D38A4ECBE03 v1
231