Siemens ETU776 - Protection Switching Capabilities; I²t Short-circuit Protection Switching; Changeable Parameter Sets Functionality; I²t Ground-fault Protection Switching

13WL Circuit Breaker Selection and Application Guide
WL Circuit Breaker
ETU Function Overview
1
Extended Instantaneous Protection (EIP) allows the WL breaker to be applied at the withstand rating available
of the breaker with minus 0% tolerance; that means no instantaneous override whatsoever. EIP further – not available
enables the circuit breaker to be applied up to the full instantaneous rating of the breaker on systems
optional
where the available fault current exceeds the withstand rating.
2
Ground Fault Module cannot be removed after installation.
Basic functions ETU745
Long-time overcurrent protection
Function can be disabled –
Setting range I
R
= I
n
x ... 0.4, 0.45, 0.5, 0.55, 0.6,
0.65, 0.7, 0.8, 0.9, 1
Switch-selectable overload protection (I
2
t or I
4
t dependent function)
Setting range of time delay class t
R
at I
2
t
(seconds) 2, 3.5, 5.5, 8, 10,
14, 17, 21, 25, 30
Setting range of time delay t
R
at I
4
t
(seconds) 1, 2, 3, 4, 5
Thermal memory
(via slide switch)
Phase loss sensitivity set t
sd
=20 ms (M)
Neutral protection
Function can be disabled (via slide switch)
N-conductor setting range I
N
= I
n
x ... 0.5 ... 1
Short-time overcurrent protection
Function can be disabled (via rotary switch)
Setting range I
sd
= I
n
x ... 1.25, 1.5, 2, 2.5,
3, 4, 6, 8, 10, 12
Setting range of time delay t
sd
, fixed
(constant time in seconds) 0.02 (M), 0.1, 0.2,
0.3, 0.4, OFF
Setting range of time delay I
sd
at I
2
t
(seconds) 0.1, 0.2, 0.3, 0.4
Zone Selective Interlocking (ZSI) function per CubicleBUS module
Instantaneous overcurrent protection
Function can be disabled
Extended Instantaneous Protection Instantaneous is active when disabled
Setting range I
i
= I
n
x ... 1.5, 2.2, 3, 4, 6, 8, 10, 12
0.8 x I
cw
= Max,
Ground fault protection
2
O (field installable module)
Trip and alarm function
Detection of the ground fault current
by residual summing method
Detection of the ground fault current
by direct sensing method
Setting range of the I
g
for trip A, B, C, D, E (100 ... 1200A)
Setting range of the I
g
for alarm A, B, C, D, E (100 ... 1200A)
Setting range of the time delay t
g
(fixed seconds) 0.1, 0.2, 0.3, 0.4, 0.5
Setting range time delay t
g
at I
2
t 0.4, 0., 0.3, 0.4, 0.5
ZSI ground function per CubicleBUS module
L
N
S
I
G
Courtesy of NationalSwitchgear.com