Toshiba GR200 Series - Page 1729

6F2S1914 (0.49)
GRL200 (Soft 033 & 037)
- 1706 -
Table K-7 CT Requirement defined by V
k
(Special case)
Td
[ms]
Requirement 1
Requirement 2
35
V
k
≧ I
fmax
(R
ct
+ R
2
)×3
V
k
> Max{I
LMAX
+ I
fmin
/2, I
fmaxout
} ×(R
ct
+ R
2
)×14.4
50
V
k
≧ I
fmax
(R
ct
+ R
2
)×3
V
k
> Max{I
LMAX
+ I
fmin
/2, I
fmaxout
}× (R
ct
+ R
2
)×20
75
V
k
≧ I
fmax
(R
ct
+ R
2
)×4
V
k
> Max{I
LMAX
+ I
fmin
/2, I
fmaxout
}× (R
ct
+ R
2
)×28.8
100
V
k
≧ I
fmax
(R
ct
+ R
2
)×4
V
k
> Max{I
LMAX
+ I
fmin
/2, I
fmaxout
}× (R
ct
+ R
2
)×36.8
150
V
k
≧ I
fmax
(R
ct
+ R
2
)×8
V
k
> Max{I
LMAX
+ I
fmin
/2, I
fmaxout
} ×(R
ct
+ R
2
)×50.4
V
k
: Knee point voltage [V]
R
ct
: Secondary CT resistance [ohms]
R
2
: Actual secondary burden [ohms]
I
fmax
: Maximum secondary fault current
I
Lmax
: Maximum secondary load current
Max{I
LMAX
+ I
fmin
/2, I
fmaxout
}: The larger of (I
LMAX
+ I
fmin
/2) and I
fmaxout
I
fmin
: Minimum fault current
I
fmaxout
: Maximum out-flowing fault current for the special condition
<Accuracy limit factor of CTs is given>
Table K-8 CT Requirement defined by n’
Td [ms]
Requirement 1
Requirement 2
35
n’ I
n
≧ 3.75 × I
fmax
n’ I
n
> Max{I
LMAX
+ I
fmin
/2, I
fmaxout
}×18
50
n’ I
n
≧ 3.75 × I
fmax
n’ I
n
> Max{I
LMAX
+ I
fmin
/2, I
fmaxout
}×25
75
n’ I
n
≧ 5 × I
fmax
n’ I
n
> Max{I
LMAX
+ I
fmin
/2, I
fmaxout
}×36
100
n’ I
n
≧ 5 × I
fmax
n’ I
n
> Max{I
LMAX
+ I
fmin
/2, I
fmaxout
}×46
150
n’ I
n
≧ 10 × I
fmax
n’ I
n
> Max{I
LMAX
+ I
fmin
/2, I
fmaxout
}×63
n
RR
RIR
n
ct
ctnVA

+
+
=
2
2
/
'
(K-1)
n’ : Equivalent accuracy limit factor defined by the equation above.
I
n
: Secondary rated current
R
VA
: Rated secondary burden [VA]
R
ct
: Secondary CT resistance [ohms]
R
2
: Actual secondary burden [ohms]
n : Rated accuracy limit factor
I
fmax
: Maximum secondary fault current
I
Lmax
: Maximum secondary load current
Max{I
LMAX
+ I
fmin
/2, I
fmaxout
}: The larger of (I
LMAX
+ I
fmin
/2) and I
fmaxout
I
fmin
: Minimum fault current
I
fmaxout
: Maximum out-flowing fault current for the special condition