Siemens SENTRON 3VA2 - Page 82

Description
2.6 Protection system
3VA molded case circuit breakers with IEC certificate
80 Manual, 03/2019, A5E03603177010-03
Neutral conductor protection and 3VA2 molded case circuit breakers
The following versions of 3VA2 molded case circuit breaker have neutral conductor protection:
● All 3-pole versions with external current transformer for N conductor
● All 4-pole versions
The tripping systems of the 5-series and 8-series ETUs enable overdimensioning of the
neutral conductor protection up to 160% of I
n
. This might be necessary to provide protection
against third-order harmonics and multiples thereof.
N Neutral conductor protection
1)
At rated operational currents I
n
≤ 63 A: I
N
= 40 % … 100 % I
n
2)
Applies to I
n
> 63 A
3)
Dependent on circuit breaker size and rated operational current
Parameters of the neutral conductor protection function
● Tripping current I
N
:
Adjustable as a proportion of the current setting (I
r
) for overload protection
● Tripping delay:
Corresponds to the delay setting (t
r
) for overload protection
● Tripping current of the short-time delayed short-circuit protection:
Corresponds to the short-time delayed short-circuit protection (I
sd
)
● Tripping delay:
Corresponds to the delay setting for short-time delayed short-circuit protection (t
sd
)
● Instantaneous short-circuit protection:
Corresponds to the tripping current (I
i
) for instantaneous short-circuit protection
You will find information about setting options in chapter Line protection applications of 3VA
molded case circuit breakers (Page 110).