7SR11 & 7SR12 Performance Specification
ยฉ2017 Siemens Protection Devices Limited Chapter 3 Page 54 of 56
3.3 60CTS & 60CTS-I Current Transformer Supervision
3.3.1 Reference
Parameter Value
I
thresh
Current Threshold
0.05, 0.1โฆ 2 xIn
I
Applied Current
(for operate time)
Healthy CT
Phases
5 x I
thresh
Failed CT phase 0
t
d
Delay setting
0.3, 20.00, 20.50โฆ 100, 101โฆ
1000, 1010โฆ 10000, 10100โฆ
14400 s
Directional Relays have additional VT settings
V
thresh
Voltage Threshold 7, 8โฆ 110V
3.3.2 Current & Voltage Threshold
Attribute Value
I
op
CT failed current level
100 % I
thresh
, ยฑ 5% or ยฑ 1% In
Reset level
90 % I
op,
ยฑ 5% or ยฑ 1% In
V
op
CT failed voltage level
100 % V
thresh
, ยฑ 2% or ยฑ 0.5V
Reset level
110 % V
op
, ยฑ 2 % or ยฑ 0.5V
Repeatability
ยฑ 1 %
Variation
-10 ยฐC to +55 ยฐC
โค 5 %
f
nom
ยฑ 5 %
harmonics to f
cutoff
โค 5 %
3.3.3 Operate and Reset Time
Attribute Value
t
basic
Basic operate time
50 ms ยฑ 20ms
Operate time
t
d
+ t
basic
, ยฑ 1 % or ยฑ 20ms
Repeatability
ยฑ 1 % or ยฑ 20ms