Section 12 Secondary System Supervision; Current Circuit Supervision (87); Identification; Application - ABB Relion 670 Series Applications Manual

1MRK 511 358-UUS A
Section 12
12.1

Current circuit supervision (87)

12.1.1

Identification

Function description
Current circuit supervision
12.1.2

Application

Open or short circuited current transformer cores can cause unwanted operation of many
protection functions such as differential, ground-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 (87) 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.
12.1.3

Setting guidelines

GlobalBaseSel : Selects the global base value group used by the function to define ( IBase ), ( VBase )
SBase ).
and (
Current circuit supervision CCSSPVC (87) 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.
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.
IEC 60617 ANSI/IEEE C37.2
identification device number
- 87
Section 12
Secondary system supervision
IP14555-1 v5
M14870-1 v5
M12395-13 v8
M12397-17 v7
245