Page 136 - Surge-Protection-E_0.pdf

Alt- / Auslaufprodukte / Alternativprodukte

SPDs for Information Technology Systems
Use of arresters
The application guide CLC TS 61643-22 / IEC 61643-22 describes principles
for selecting and using arresters. It defines basic requirements on the loads
with which arresters are tested for using arresters at the different zone
transitions of the lightning protection zone concept according to IEC / EN
62305. The protection components at the different lightning protection
zones must therefore cope with with defined pulse categories.

Lightning protection zone LPZ 0 / 1 LPZ 1 / 2 LPZ 2 / 3

Entrance point into the building D1
Sub-distribution board C2
Terminal device C1
Impulse category requirements for SPDs for information technology applications
according to the lightning protection zone concept
Selection of arresters for information technology systems To make the selection of arresters easier for the user, the SPD class (TYPE
The following must be observed when selecting arresters: classification) for Yellow / Line arresters is based on that of arresters
– Protective effect (Red / Line) for power supply systems. However, so-called combined arrest-
[Yellow / Line SPD class (discharge capacity and voltage protection ers can also be used universally at the different lightning protection zones.
level)] Consequently, the different impulse categories (D1, C2, C1) for the arrest-
– System parameters ers are specified according to their possible point of use.
(system voltage, nominal current and transmission parameters)
– Installation environment LPZ EN / IEC 61643-21 EN / IEC 61643-11
(design, connection conditions and approvals)
0 / 1 D1 | 0.5 … 2.5 kA (10/350 μs) Type 1 / I
The selection guide according to interface / signal on pages 135 – 154
facilitates the selection of the right arrester. 1 / 2 C2 | 1 … 5 kA (8/20 μs) Type 2 / II
2 / 3 C1 | 0.25 … 1 kA (8/20 μs) Type 3 / III
Relevant product standard for arresters: Impulse categories and arrester classification for arresters in information technol-
IEC / DIN EN 61643-21 ogy and power supply systems
Low-voltage surge protective devices – Part 21: Surge protective devices
connected to telecommunications and signalling networks – Performance Immunity of terminal equipment to be protected
requirements and testing methods.
During electromagnetic compatibility (EMC) tests, electrical and electron-
ic equipment (devices) must have a certain immunity to conducted inter-
Discharge capacity ferences (surges). The requirements on the immunity and the test set-up
According to IEC / EN 61643-21 arresters must be tested with at least one are described in IEC / EN 61000-4-5.
impulse voltage and impulse current from the table below with the spec- Since the devices are used in different electromagnetic environments, they
ified quantity of impulses. Further tests may be performed – even with must have different immunities. The immunity of a device depends on the
different impulse values or quantities. The max. voltage level measured test level. To classify the different immunities of terminal equipment, test
during the test(s) at the output of the device is specified as voltage pro- levels are subdivided into four different levels (1 to 4). Test level 1 places
tection level UP. Category C above all represents interference impulses the lowest requirement on the immunity of terminal equipment. The test
with a steep rate of rise and low energy, while interference impulses of level is specified in the arrester documentation or can be requested from
category D are supposed to simulate high energy loads caused by injected the manufacturer of the arrester.
partial lightning currents. The relevant category is specified in the techni-
cal data of the arresters [see discharge capacity (In, Iimp) and voltage pro-
Corresponds to the charging
Test levels 1 – 4
tection level (UP)]. according to EN 61000-4-5 voltage of the test generator
Minimum 1 0.5 kV
Cate- Type of Impulse Impulse Test
gory test voltage current quantity of for 2 1 kV
impulses 3 2 kV
0.5 kV 0.25 kA 4 4 kV
C1 to 2 kV, to 1 kA, 300
1.2/50 μs 8/20 μs
fast 2 kV 1 kA Protective effect of arresters
C2 rate of to 10 kV, to 5 kA, 10 Surge Yellow / Line arresters for use in information technology systems are capa-
rise 1.2/50 μs 8/20 μs arrester ble of limiting conducted interference to a safe level so that the immuni-
10 A ty of the terminal equipment is not exceeded. For example, an arrester
≥ 1 kV, with a let-through value below the EMC test values of the terminal device
C3 to 100 A, 300
1 kV/μs
10/1000 μs must be selected for a terminal device tested with test level 2:
0.5 kA Impulse voltage < 1 kV in combination with an impulse current of some
high amperes (depending on the coupling network).
D1 ≥ 1 kV to 2.5 kA, 2 *)
energy
10/350 μs
*) Lightning current arrester / Combined lightning current and surge arrester
Impulse voltages and currents (preferred values) for determining the voltage-limit-
ing characteristics (excerpt from Table 3 of IEC / EN 61643-21)

132