7.6.2 Short-circuit short time-delay overcurrent protection characteristic.
7.6.1 Long time-delay overcurrent protection characteristic
Rated current range [IR]
Error
Current [I]
Time error
Example 1: If it is known that in condition of I=6I ,
R
The tripping time setting value is 2s,
and now the circuit current I=1.5I ,
R
then the actual tripping time T can be worked out by:
R
(1.5I )2×T =(6I )2×2. The answer is obtained as T =32s
R
R
R
R
Rated current range [Isd]
Error
Current [I]
Operating time [tsd(s)]
Time error
(1.5~10)I
R
+OFF(Power off)
No action
Time
-
delay
action
2
2
anti-time-limit delay:I Tsd=(10I ) tsd
R
Example 2: If it is known that the short-time delay
setting current is Isd=3I ,
R
then the tripping time is set as tsd=0.2s
in the setting position of inverse
2
time limit (1 t ON). Now the current is 7I
R
in the line current, then the short-time delay tripping time
can be worked out by calculation:
1.5Isd=1.15×3I =3.45I
R
R
Then I=7I
＞1
.15Isd
R
And because I=7I
＜
10I
R
R
2
2
So accotding to I ×Tsd=(10I) tsd
2
2
(7I ) ×Tsd=(10I ) ×0.2
R
R
Tsd=0.41s
Heat capacity measurement
Standard type (M type)
Multifunction type (H type)
P Function
1.Voltage measurement;
2.Voltage unbalance measurement;
3.Frequency measurement;
4.Phase sequence measurement;
5.Electric energy measurement;
6.Power measurement;
7.Power factor measurement;
8.Earth-current grounding protection;
9.Leakage protection;
10.Load monitoring function;
11.Quadruple D0 output function;
12.DI input function;
13.Regional interlocking function;
14.Under and over voltage protection;
H Function
None
1.Voltage measurement;
2.Voltage unbalance measurement;
3.Frequency measurement;
4.Phase sequence measurement;
5.Electric energy measurement;
6.Power measurement;
7.Power factor measurement;
8.Earth-current grounding protection;
9.Leakage protection;
10.Load monitoring function;
11.Quadruple DO output function;
12.DI input function;
13.Regional interlocking function;
14.Under and over voltage protection;
15.Measurement of harmonic current;
16.Neutral phase protection
T(s)
X In
0.1 0.2
0.3 0.4
0.6
1
2 3 4 5 6 8 10
20 30
0.05
0.8
10000
5000
1000
500
200
100
50
20
10
5
2
1
0.5
0.2
0.1
0.05
0.02
0.01
Ig=(0.2-1)In
MAX 1200A
MIN 120A
2
I ON
2
I t OFF
0.5
Overcurrent protection characteristics
Neutral line (earthing) fault protection characteristic
7.6 Characteristic parameters of the standard type intelligent controller
T(s)
X IR
0.2
0.3
0.6
1
2
3 4 5
8 10
20
30
50
80
0.5
0.8
40
60
10000
5000
1000
500
200
100
50
20
10
5
2
1
0.5
0.2
0.1
0.05
0.02
0.01
T =(1~30)s
R
8 10
20
30
2
1.5
4
3
5
6
2
I t ON
Isd=
（
1.5~10
）
I
R
I
R
=(0.4-1)In
Ii=
（
2~15)In
2
I t OFF
Isd=
（
1.5~10
）
I
R
(0.4~1)
In
±10%
≤1.05I
R
>1.30I
R
1.5IR
2.0IR
6.0IR
No actuation within 2h
Operating time [tR(s)]
＜
1h and then actuate
16
9
1
32
18
2
64
36
4
128
72
8
192
108
12
256
144
16
320
180
20
384
216
24
480
270
30
±1
5
%
±1
5
%
±1
5
%
0.1 0.2 0.3 0.4
0.1 0.2 0.3 0.4
<0.85Isd
>1.15Isd
2
I t OFF
2
I t ON
I>10IR
2
I t ON
I
≤10
IR
NA8G
Air Circuit Breaker
P-032
P-031
NA8G
Air Circuit Breaker
Explanation for parameter setting
Current of long time-delay overcurrent protection: I =(0.4-
R
0.5-0.6-0.7-0.8-0.9-0.95-0.98-1)
×
In, optional.
The long-time delay tripping time represents the inverse-
time limit characteristic, and nine optional settings are
readily available for tripping time in case of 6IR:TR=(1-2-4-8-
12-16-20-24-30)s.
For setting, insert a small slotted screwdriver to the knob
groove as shown in the right drawing, gently turn it to make
the arrow of the knob point at the current and time set as
required. As shown in the figure, the over current long time
delay protection current setting value I =0.6In, and the delay
R
tripping time is 2s (in the condition of 6I ).
R
Explanation
for
parameter
setting
Current
of
short
-
circuit
short
time
-
delay
overcurrent
protection
:
Isd
=(1.5-2-2.5-3-4-5-6-8-10)×
I
,
optional
.
R
There
are
nine
settings
for
the
short
-
circuit
short
time
-
delay
tripping
time
,
wherein
4
settings
represent
the
definite
-
time
2
limit
characteristic
(
i
.
e
.,
I t
OFF
), 4
seetings
the
inverse
-
time
limit
characteristic
,
and
1
setting
the
function
of
closing
the
short
-
circuit
short
time
-
delay
(
X
).
When
the
tripping
time
is
set
as
definite
-
time
limit
operating
characteristic
(
i
.
e
.,
the
arrow
points
at
the
off
area
),
the
tripping
time
can
be
selected
as
tsd
=(0.1
s
-0.2
s
-0.3
s
-0.4
s
-
x
(
i
.
e
.,
the
function
of
closing
the
short
-
time
delay
).
When
the
tripping
time
is
set
as
inverse
-
time
limit
operating
2
characteristic
(
i
.
e
.,
I t
ON
),
there
are
two
cases
: ①
the
case
of
1＞1.15
Isd
and
1＞10
I
represents
the
definite
-
time
limit
; ②
R
the
case
of
1＞1.15
Isd
and
I
≤10
I
represents
the
inverse
-
time
R
limit
characteristic
and
the
actual
tripping
time
is
calculated
2
2
according
to
the
formula
I Tsd
=(10
I
)
tsd
,
where in
I
is
the
line
R
current
,
Tsd
the
actual
tripping
time
,
and
tsd
the
setting
tripping
time
.
The
method
for
setting
the
current
and
time
for
the
short
-
circuit
short
time
-
delay
overcurrent
protection
is
similar
to
that
for
over
long
time
-
delay
overcurrent
protection
.
As
shown
in
the
figure
,
the
current
for
the
short
-
circuit
short
time
-
delay
overcurrent
protection
is
3
I
,
and
the
R
tripping
time
is
set
as
tsd
=0.2
s
in
the
setting
position
of
2
inverse
time
limit
(
I t
ON
).
Summary of Contents for NA1
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