Mitsubishi Electric AE-SW Series Instruction Manual page 28

< Example for ETR characteristics setting >
For setting calculation, take AE1600-SW 1600A WS1G1 relay for example.
Current settings and operating times are calculated.
Ir=0.8 ✕ In
=0.8 ✕ 1600A
=1280A
Iu=0.9 ✕ Ir
=0.9 ✕ 1280A
=1152A
Isd=3 ✕ Ir
=3 ✕ 1280A
=3840A
Ig=0.1 ✕ In
=0.1 ✕ 1600A
=160A
Ip=0.8 ✕ Iu
=0.8 ✕ 1152A
=921.6A
In=1600A
Table 28-1 Calculated current and operating time
In (CT rating) =1600A
Ir =1280A
Iu =1152A
T =100sec.±20% (at 2304A)
L
Isd =3840A±15%
Tsd =0.3sec.±20% (at 5760A)
E − 28
Fig. 28-1
Ii =15360A±15%
Ip =921.6A±10%
Tp =50sec.±20% (at 2304A)
Ig =160A±20%
=0.8sec. (at 240A) ±20%
Tg
—
In = Rated current (CT rating)
Ii=12 ✕ Ir
Ir = Rated current setting
=12 ✕ 1280A
Iu = Uninterrupted current
=15360A
(non-breaking current)
T = Long time delay pick-up current
L
Isd = Short time delay pick-up current
Tsd = Short time delay tripping time
T =100 sec.
L
Ii = Instantaneous pick-up current
Operating time at
Ip = Pre-alarm pick-up current
current twice as high
Ig = Ground fault pick-up current
as lu, 1152 ✕ 2=2304A
Tg = Ground fault operating time
Tsd=0.3 sec.
Operating time at current
1.5 times as high as Isd,
3480 ✕ 1.5=5760A
Tg=0.8 sec.
Operating time at current
1.5 times as high as Ig,
160 ✕ 1.5=240A
1
Tp= T
L
2
1
For of T at 2304A:
L
2
100 ✕ 0.5=50 sec.