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BETA Protecting
Overvoltage Protection Devices
Configuration
6/20
Siemens ET B1 · 10/2008
6
*
You can order this quantity or a multiple thereof.
■
Overview
Overvoltage protection devices (SPD)
Overvoltage protection devices (SPD: Surge Protection Device):
equipment whose main components comprise spark gaps
(
discharge paths) and/or voltage-independent resistors (varis-
tors, suppressor diodes). Overvoltage protection devices serve
to protect other electrical equipment and electrical systems
against unacceptably high overvoltages and to establish equi-
potential bonding.
Overvoltage protection devices are categorized:
a) According to their application:
•
Overvoltage protection devices for systems and devices in
power systems
•
Overvoltage protection devices for plants and devices in
information systems for protecting modern electronic devices
in telecommunication and signal processing systems against
the indirect and direct effects of lightning strikes and other
transient overvoltages
•
Spark gaps for grounding systems or for equipotential bonding
b) According to their surge current discharge capacity and their
protective action:
•
Type 1 lightning arresters for influences as a result of direct or
close-up strikes for the protection of installations and equipment
•
Type 1 and 2 combination surge arresters in one device for
influences as a result of direct or close-up strikes for the
protection of installations, equipment and terminal equipment.
•
Type 1 and type 2 surge arresters for remote strikes, switching
overvoltages, as well as electrostatic discharges for the
protection of installations, equipment and terminal equipment.
Requirement categories of arresters
Lightning current and overvoltage protection is only effective if
the pertinent insulation resistance of plant sections is also taken
into account. To do this, the impulse withstand voltage of the
different overvoltage categories is adapted to suit the protection
level U
p
of the different overvoltage protection devices.
The international standard IEC 60664-1 (EN 60664-1) distinguishes
between four impulse withstand voltage categories for low-voltage
devices. For low-voltage systems with a rated voltage of
230/400
V in particular, the following categories apply:
The following table shows the breakdown of lightning and surge
arresters into requirement categories.
Furthermore, the following country-specific product standards
also apply:
•
Italian: CEI EN 61643-11
•
Austria: ÖVE/ÖNORM E 8001.
Note:
You can download the technology primer, "Lightning current and
overvoltage protection" on the Internet (www.siemens.com/beta)
or obtain a copy from your local Siemens representative.
kWh
I2_13943
S
P
D
S
P
D
6
kV
4
kV
2,5
kV
< 4 kV
< 1,5 kV
< 1,3 kV
S
P
D
Type 1
Requirement
category
Rated impulse
withstand voltage
Protection level
Type 2
Type 3
Surge voltages
Category Impulse
withstand
voltage
Description
IV
6
kV
Devices at the infeed of the installation,
e.g. main distribution boards, E-counters,
overcurrent circuit breakers, ...
III
4
kV
Devices that are part of the permanent
installation:
e.g distribution boards, protective devices, ...
II
2.5
kV
Devices for connection to the permanent
installation, e.g. household appliances
I
1.5
kV
Extremely sensitive devices
e.g. electronic devices, ...
German Product
Standard
EN 61643-11
International
Standard
IEC 61643-1
Designation
Type 1
Class I
Lightning arresters
Type 2
Class II
Surge arresters for
distribution boards
Type 3
Class III
Surge arresters for
terminal equipment
© Siemens AG 2008