ABB Relion 670 Series Applications Manual page 307

1MRK 511 401-UEN Rev. K
Section 14
14.1 Current circuit supervision CCSSPVC
14.1.1 Identification
Function description
Current circuit supervision
14.1.2 Application
Open or short circuited current transformer cores can cause unwanted operation of many
protection functions such as differential, earth-fault current and negative-sequence current
functions. When currents from two independent three-phase sets of CTs, or CT cores,
measuring the same primary currents are available, reliable current circuit supervision can be
arranged by comparing the currents from the two sets. If an error in any CT circuit is detected,
the protection functions concerned can be blocked and an alarm given.
In case of large currents, unequal transient saturation of CT cores with different remanence or
different saturation factor may result in differences in the secondary currents from the two CT
sets. Unwanted blocking of protection functions during the transient stage must then be
avoided.
Current circuit supervision CCSSPVC must be sensitive and have short operate time in order to
prevent unwanted tripping from fast-acting, sensitive numerical protections in case of faulty
CT secondary circuits.
14.1.3 Setting guidelines
GlobalBaseSel : Selects the global base value group used by the function to define IBase , UBase
SBase . Note that this function will only use IBase value.
and
Current circuit supervision CCSSPVC compares the residual current from a three-phase set of
current transformer cores with the neutral point current on a separate input taken from
another set of cores on the same current transformer.
IMinOp : It must be set as a minimum to twice the residual current in the supervised CT circuits
under normal service conditions and rated primary current.
Ip>Block : It is normally set at 150% to block the function during transient conditions.
The FAIL output is connected to the blocking input of the protection function to be blocked at
faulty CT secondary circuits.
Bay control REC670
Application manual
Secondary system supervision
IEC 61850
identification
CCSSPVC
Open CT circuits creates extremely high voltages in the circuits which is
extremely dangerous for the personnel. It can also damage the insulation and
cause new problems. The application shall, thus, be done with this in
consideration, especially if the protection functions are blocked.
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Secondary system supervision
IEC 60617 ANSI/IEEE C37.2
identification device number
- 87
Section 14
IP14555-1 v5
M14870-1 v5
M12395-13 v9
M12397-17 v8
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