Toshiba GR200 Series Instruction Manual page 1723

R : Actual secondary burden [ohms]
2
I : Maximum secondary fault current
fmax
I : Maximum secondary fault current at the zone 1 reach point
f_z1_max
I : Maximum secondary fault current for a close-up reverse fault
f_rev_max
I : Maximum secondary load current
Lmax
<Accuracy limit factor of CTs is given>
Table K-2 CT Requirement defined by n'
Td [ms]
35
50
75
100
150
Td [ms]
35
50
75
100
150
=
n '
n' : Equivalent accuracy limit factor defined by the equation above.
I : Rated current at CT secondary
n
R : Rated secondary burden [VA]
VA
R : Secondary CT resistance [ohms]
ct
R : Actual secondary burden [ohms]
2
n : Rated accuracy limit factor
I : Maximum secondary fault current
fmax
I : Maximum secondary fault current at the zone 1 reach point
f_z1_max
I : Maximum secondary fault current for a close-up reverse fault
f_rev_max
I : Maximum secondary load current
Lmax
Note : The values in the table are based on the following assumption.
- 100% DC component is superimposed.
- Only one CT is saturated.
- No remnance flux is assumed.
Requirement 1
n' I ≧ 3.75 × I
n
n' I ≧ 3.75 × I
n
n' I 5 × I
≧
n
n' I 5 × I
≧
n
n' I 10 × I
≧
n
Requirement 3
n' I 2.5 × I
≧
n
n' I ≧ 3.75 × I
n
n' I 7.5 × I
≧
n
n' I 7.5 × I
≧
n
n' I 7.5 × I
≧
n
+
2
R / I R

VA n ct
n
+
R R
2 ct
- 1700 -
n' I
fmax n
n' I
fmax n
n' I
fmax n
n' I
fmax n
n' I
fmax n
n' I
f_rev_max
n' I
f_rev_max
n' I
f_rev_max
n' I
f_rev_max
n' I
f_rev_max
(K-1)
6F2S1914 (0.49)
Requirement 2
7.5 × I
≧
f_z1_max
≧ 8.75 × I
f_z1_max
10 × I
≧
f_z1_max
10 × I
≧
f_z1_max
10 × I
≧
f_z1_max
Requirement 4
≧ I
×18
n Lmax
≧ I
×25
n Lmax
≧ I
×36
n Lmax
≧ I
×46
n Lmax
≧ I
×63
n Lmax
GRL200 (Soft 033 & 037)