Siemens Sivacon S8 Planning Information

92
SIVACON S8 Planning Principles – Technical annex
(EMC). From experience the TN-S system has the best
cost-benefit ratio of electric networks at the low-voltage
level. To determine the type of connection to earth, the
entire installation from the power source (transformer) to
the electrical consumer must be considered. The low-volt-
age switchboard is merely one part of this installation.
10.1 Power supply systems according
to their type of connection to earth
The power supply systems according the type of connec-
tion to earth considered for power distribution are de-
scribed in IEC 60364-1. The type of connection to earth
must be selected carefully for the low-voltage network, as
it has a major impact on the expense required for protective
measures (Fig. 10/1). On the low-voltage side, it also
influences the system's electromagnetic compatibility
10 Technical annex
Fig. 10/1: Systems according to the type of connection to earth in accordance with IEC 60364-1
TN system: In the TN system, one operating line is directly earthed; the exposed conductive parts in the electrical installation are connected
to this earthed point via protective conductors. Dependent on the arrangement of the protective (PE) and neutral (N) conductors,
three types are distinguished:
TT system: In the TT system, one operating line is directly
earthed; the exposed conductive parts in the
electrical installation are connected to earthing
electrodes which are electrically independent of the
earthing electrode of the system.
IT system: In the IT system, all active operating lines are
separated from earth or one point is connected
to earth via an impedance.
First letter = earthing condition of the supplying
power source
T = direct earthing of one point (live conductor)
I = no point (live conductor) or one point of the power
source is connected to earth via an impedance
Second letter = earthing condition of the exposed
conductive parts in the electrical installation
T = exposed conductive parts are connected to earth
separately, in groups or jointly
N = exposed conductive parts are directly connected to the
earthed point of the electrical installation (usually
N conductor close to the power source) via protective
conductors
Further letters = arrangement of the neutral conductor and
protective conductor
S = neutral conductor function and protective conductor function
are laid in separate conductors.
C = neutral conductor function and protective conductor function
are laid in one conductor (PEN).
Power
source
Electrical installation
a) TN-S system:
In the entire system, neutral (N)
and protective (PE) conductors
are laid separately.
b) TN-C system:
In the entire system, the functions
of the neutral and protective conductor
are combined in one conductor (PEN).
c) TN-C-S system:
In a part of the system, the functions
of the neutral and protective conductor
are combined in one conductor (PEN).
Power
source
Electrical installation
Power
source
Electrical installation
Power
source
Electrical installation
Power
source
Electrical installation
1
2
3
4
Exposed conductive part
High-resistance impedance
Operational or system earthing R
B
Earthing of exposed conductive parts R
A
(separately, in groups or jointly)
L1
N
L2
L3
PE
1
3
1 1
3
1 1
3
1
L1
PEN
L2
L3
L1
PEN PE
N
L2
L3
1
3 4
1
2
3
4
L1
N
L2
L3
R
B
R
A
L1
N
L2
L3
R
B
R
A

Siemens Sivacon S8 Specifications

General

Brand	Siemens
Model	Sivacon S8
Category	Industrial Equipment
Language	English