ABB 615 Series - Current Transformer Supervision for High-Impedance Protection Scheme MCS-A, MCS-B, MCS-C

6.3 Current transformer supervision for high-impedance
protection scheme MCS-A, MCS-B, MCS-C
6.3.1 Identification
Function description IEC 61850
identification
IEC 60617
identification
ANSI/IEEE C37.2
device number
Current transformer supervision for
high-impedance protection scheme for
phase A
HZCCASPVC
MCS I_A MCS-A
Current transformer supervision for
high-impedance protection scheme for
phase B
HZCCBSPVC
MCS I_B MCS-B
Current transformer supervision for
high-impedance protection scheme for
phase C
HZCCCSPVC
MCS I_C MCS-C
6.3.2 Function block
ALARM
MCS-A
BLOCK
I_A ALARM
MCS-B
BLOCK
I_B ALARM
MCS-C
BLOCK
I_C
GUID-9C726422-7ED4-42AE-AED1-8C5829FE085D V1 EN
Figure 441: Function block
6.3.3 Functionality
The current transformer supervision for high-impedance protection scheme function
MCS-A, MCS-B, MCS-C is a dedicated phase-segregated supervision function to be used
along with the high-impedance differential protection for detecting the broken CT
secondary wires. The differential current is taken as an input for the protection relay.
During normal CT condition, the value of the differential current is zero. However, when
the CT is broken, the secondary differential current starts flowing and it is used for
generating alarms.
To avoid faulty operation, MCS-A, MCS-B, MCS-C should have a sensitive setting,
compared to the high-impedance differential protection. The function is likely to pick up
under through-fault conditions. However, by incorporating a high time delay (3 s or
more), the downstream protection clears the fault before an alarm is generated.
MCS-A, MCS-B, MCS-C generates an alarm when the differential current exceeds the set
limit. The function operates within the DT characteristic.
Section 6 1MAC059074-MB A
Supervision functions
854 615 series ANSI
Technical Manual