87T‑BD Transformer Differential Protection – Biased
Common Settings
Reference
Parameter
Value
ICTn Mult
Winding n ICT multiplier setting
0.25 to 3x, Δ 0.01
ICTn Conn
Winding n CT winding connections setting See
5.22 87T Transformer Differential
ICT Mult
set
Applied ICT multiplier settings (for operate
time)
W 1/2/3 = 1x
ICT Conn
set
Applied ICT connection settings (for
operate time)
W 1/2/3 = YY
Transformer Differential Protection - Biased
Reference
Parameter
Value
I
init
Setting
0.1 to 2
p.u.
, Δ 0.05
p.u.
S1
Bias slope 1
0.1x to 0.7x, Δ 0.05
S1L
Bias slope 1 limit
1 to 20 ⋅ I
rated
, Δ 0.5
S2
Bias slope 2
1x to 2x, Δ 0.05
I
Applied current (for operate time)
0 to 3 ⋅ I
op
(switched)
DTL
Delay setting
0 to 1 s, Δ 0.005 s
Operate and Reset Level
Attribute
Value
I
op
Operate level
I
BIAS
0 to 1
p.u.
: I
op
> I
init
I
BIAS
1
p.u.
to S1L: I
op
> S1(I
BIAS
- 1) + I
init
I
BIAS
> S1L: I
op
> S2 (I
BIAS
- S1L) + S1(S1L - 1)
+ I
init
Operate level
± 10 % of I
op
or ± 0.1
pu
Reset level
≥ 90 % of I
op
Repeatability
± 2 %
Transient overreach
≤ 5 %
Variation IEC
60255-1
-10 °C to +55 °C
≤ 5 %
f
rated
± 5 %
≤ 5 %
Operate Time
Attribute
Value
t
basic
Element basic operate time (Inrush action:
Enabled)
3 ⋅ I
op
, < 30 ms
t
op
Operate time following delay
t
basic
+ DTL, ± 1 % or ± 10 ms
10.32
10.32.1
10.32.2
Technical Data
10.32 87T‑BD Transformer Differential Protection – Biased
Reyrolle 7SR5, Transformer Protection Device, Device Manual
499
C53000-G7040-C015-1, Edition 11.2019