Shihlin electric BW-2000, Manual, Page: 9 / 42

ACB-OB
6
AIR CIRCUIT BREAKER
3.2.2 Short-circuit Short time delay Protection Characteristics
Intelligent controller's short-circuit Short time delay protection methods comprises inverse time protection and
definite time restriction protection.
1. Inverse time protection: When the fault current exceeds the present setting current value but is smaller than
the maximum setting short-circuit current (10Ir), the controller will carry out protection
(10I
r
) 2 *T
sd
=I 2 *t
according to the inverse time curve. When the fault current exceeds the maximum setting short-circuit
current (10Ir), the controller will carry out delay protection according to the present delay setting value.
2. Definite time protection: When the fault current exceeds the present setting short-circuit current, the
controller will carry out delay protection according to the present delay setting value.
3. When overload long-delay setting time Tr = 5s or 10s, the short-circuit protection enforced setting will be
definite time protection (unadjustable).
Technical parameters of short-circuit short time delay protection characteristics are listed in Table 2.
3.2.3 Short-circuit Instantaneous Protection Characteristics
The operation time of short-circuit instantaneous protection (including the original breaking time of the circuit
breaker) should be less than 100ms. Parameters of the controller's short-circuit instantaneous protection
characteristics are listed in Table 3.
Table 2. Technical parameters of short-circuit short time delay protection characteristics
Table 3. Technical Parameters of Short-circuit short time delay Protection Characteristics
Note: When delay setting value is set to “ I
2
T ON ” , the controller will carry out protection according to the inverse time method,
and the definite time function will automatically become invalid. When delay setting value is set to “ I
2
T OFF ” , the
controller will carry out protection according to the definite time setting, and the inverse time function will automatically
become invalid.
Adjusting steps:
2-4-6-8-10-11-12-15 + OFF
Ii =
（
2~15
）
In
Current
setting value
Operation
time
Tripped between 0.9 and 1.1Ir
Operation
characteristics
< 100ms
（
including the original break time of the circuit breaker
）
instantaneous
Adjusting steps:
1.5-2-2.5-3-4-5-6-8-10
Isd =(1.5~10)Ir
Current
setting value
Adjusting steps:
I
2
T on = 0.1-0.2-0.3-0.4(@10Ir)+OFF
I
2
T off = 0.1-0.2-0.3-0.4
Tsd=(0.1~0.4)s
Time delay
setting value
Tripping between 0.9 and 1.1Isd
Operation
characteristics
I
2
T / definite time
Operation
curve
15 minute / off ( Cut off the power of the controller for reset)
Short time delay
Thermal
memory function