The installation of SPD
should pay attention to the following issues:
(
1
)
The first level of protection of the
SPD
should be close to the total equipotential connecting terminals of the building's incoming wires
At the second and third level of protection of
SPD
should be installed as close as possible to the protected equipment. >should be installed as close as possible to the protected equipment.
(
2
) The wires from the surge protector to the equipotential connection should be as short and straight as possible.
(
3
) In order to meet the information system equipment to withstand the energy requirements,
SPD
installation can be multi-stage matching
combination, in the multi-stage matching should be considered
SPD
between the energy match, when there is a continuation of the current should be strung in the line
circuit. Decoupling device. When available, it is appropriate to use the same manufacturer's similar products, and require the factory
to provide its installation distance requirements between the various levels of products. When accurate data is not available, the line length between voltage
switching type and voltage-limiting type
SPD
is less than
10
meters and the line length between voltage-limiting type
SPD
is less than
5
meters, it is appropriate to connect decoupling device in series. device.
(
4
)
In the same power supply system,
when the protective
voltage level
of the SPD
installed at the start of the power supply unit
is
Up
≤50% of the withstand voltage level of the equipment protected at the end
, it is recommended to connect a series decoupling device. 50%
, only one level of surge
protector can be installed.
(
5
)
It is necessary to consider the effect on the operation of the information system equipment of overcurrents or ground faults that may arise after degradation or end of life
and
therefore, overcurrent protective devices should be installed on the power supply side of the
SPDs
(e.g.
).fuses or air circuit breakers), the overcurrent protector (set up internally or externally) together with the
SPD
one
to take up a maximum short-circuit current equal to and greater than that expected at the installation, and the selection should be made taking into account the maximum overcurrent protector specified by the manufacturer of the
SPD
for his product. .
In addition
,
the rated blocking current storage value of the SPD
specified by the manufacturer
shall not be less than the expected short circuit current at the installation.
In
TT
systems
Residual current protective devices shall also be installed and shall be equipped with a deterioration display.
(
6
)
SPD
used in explosion hazardous places should have explosion-proof function.
(
7
) In considering the level of overvoltage protection between the equipment
Up
, if the line is not shielded
Should also take into account the induced voltage of the line, it is appropriate to consider the level of overvoltage protection of the equipment to be protected
according to the value of
80%
Consideration.
Consideration.
(
8
)
In places where the supply voltage exceeds the specified
10%
and where harmonics increase the voltage amplitude,
the zinc oxide varistor
SPD
should be increased
Uc
value in accordance with the specific conditions.
(
9
)
When a building with an information system is required to be protected by an additional
SPD
,
if the building is not
equipped with a direct lightning protection device and is not under the protection of any other building or object, it is appropriate to take measures according to the third category of lightning protection
. The building is protected against direct lightning strikes. In the case of shielding to be considered, direct lightning protection
The lightning catcher is appropriate to use the lightning net.