Environmental Engineering Reference
In-Depth Information
of initial configuration of the I&C system (discon-
nection of mounted bypasses, return to previous
set-points, etc.).
During predictive and preventive maintenance
of power unit inspections cover all components,
participating in performance of required (main)
functions of the I&C system, for example, for
regulating function- from a sensor to an end
actuating element of technological equipment,
including connecting cables. In general during
periodic control of the I&C system and predictive
preventive maintenance of power unit the follow-
ing is provided:
without its dismounting and breaking of external
connections. For checking of devices, access to
which during power unit operation is complicated
or impossible (for example, placed inside the con-
tainment), service equipment is located in safety
area on a distance from an examined product.
RESISTANCE OF FUNCTIONS
EXECUTION
General Characteristics
Peripheral equipment, SHC and their operating
stand-alone component parts have to be resistant
(immune) to external influencing factors (EIF),
which can occur in places of their location and
saved as long as required (further - working
operating conditions) and also to violation of
operation conditions considered in the design
during а limited time period (further - limit
conditions). Limit conditions can be caused, for
example, by accidents in technological equipment,
connection, disconnection, failures of ventilation
system, conditioning, power supply, providing
working operating conditions, abnormal natural
phenomena (earthquake, strokes of lightning) or
internal events (fire, flood). In general resistance
and insensibility are provided:
• Resistance measurement of electrical iso-
lation and grounding.
• Checking of accuracy of function perfor-
mance of each redundant channel and sys-
tem in whole, including with real actuators.
• Calibration of measuring channels, check-
ing of accuracy characteristics of control
and alarm channels.
• Determination of lags of output sig-
nal (command) generation and/or their
duration.
•
Executions of other inspections according
to operational documentation.
Inspections allow detecting hidden operability
failures of components, which are not detected dur-
ing continuous automatic control and tendencies
of alteration (degradation) of quantitative char-
acteristics (resistance of isolation and grounding,
errors, time lags, etc.), which in future can lead
to a function failure.
Built-in diagnostic facilities, certified service
equipment and supporting software, delivered
together with SHC, provide automation of supply
test influences (input signals), register of caused
by them responses (output signals), determination
of quantitative characteristics and archiving results
of periodic control that allows minimizing labour
intensity and duration of provided inspections.
Service equipment connects to an examined device
•
To temperature, humidity, barometric pres-
sure, ionizing radiation, corrosion-active
agents, dust (EIF environment).
•
To vibrations, strokes, seismic efects (me-
chanical EIF).
•
To double-current electric ields (electrical
EIF).
•
To water and solutions, which can afect
devices in accidents and to decontamina-
tion luids (EIF speciic environments).
•
To long-term deviations from nominal val-
ues and short-term variation of power sup-
ply (EIF power supply).
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