Environmental Engineering Reference
In-Depth Information
In case of availability of automatic gas fire-
fighting in rooms, where devices, related to safety
class 2(A), are located, they should be resistant
to reagent influence, filling a room in case of
fire fighting system actuation (type of applied
reagent is agreed with an operative organization
or customer).
nectors and other device constructive ele-
ments, deining its physical borders from a
circuit of own needs (device can have one
or several power ports).
•
If a device has several mutually redundant
power ports, test inluences are supplied by
turns to each port, at this time other ports
should be disconnected from the circuit.
Immunity to Change of
Power Parameters
•
Standards and rules for estimation of resis-
tance to changes of power parameters, test-
ing methods and estimation criteria cor-
respond to the ones speciied in NP, 2000
and State standards of Ukraine, identical
to international standards IEC, 2002a; IEC
2002c; IEC 2004.
Safety important I&C systems and SHC receive
primary power supply from a circuit of own needs
of the unit with single- or three-phase current with
a nominal voltage of 220 V or 380 / 220 V and
frequency of 50 Hz. Power supply of peripheral
equipment and operating stand-alone component
parts of SHC is directly performed from the circuit
of own needs or from secondary feed sources,
contained in the I&C system and / or SHC. The
I&C systems and SHC include facilities for dis-
tribution and protection of power circuits and if
required uninterruptable power sources.
Peripheral equipment and SHC are immune
to long-term deviations of voltage of primary
power supply, short-term changes and fluctua-
tions of voltage, power interruption, long- and
short-term changes of supply frequency, which
are possible in working and limit operation condi-
tions. Products that obtain secondary power from
sources, contained in the I&C system and SHC,
are immune to changes in parameters of primary
power supply of these sources.
Immunity is estimated on the basis of test re-
sults, during which the following rules are followed
additionally to general provisions in this chapter:
Immunity to Electromagnetic
Disturbances
I&C systems, peripheral equipment and SHC are
immune to electromagnetic EIF (electromagnetic
disturbances), which influence or can influence
them in working and limit operating conditions:
• Disturbances from electrostatic discharges.
• Disturbances from radio frequency electro-
magnetic radiation.
• Disturbances from rapid transient process-
es/ packages of impulses.
• Disturbances from power and current
spikes.
• Conductive disturbances, brought by ra-
diofrequency ields.
• Disturbances from magnetic ields of cir-
cuit frequency.
• Disturbances from impulse magnetic ields.
• Disturbances from damped oscillatory
magnetic ield.
• Oscillatory damped disturbances.
• Conductive asymmetric disturbances in a
range from 0 Hz to 150 кHz.
• Disturbances in ground lines.
• All operating stand-alone component parts
of peripheral equipment and SHC, re-
ceiving power from one source, are tests
simultaneously.
•
Points of application of test inluences are
power ports - terminal screw, clamps, con-
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