b.
Maintenance and Reliability Requirements: In general, maintenance
shall be accomplished on-line and without imposing any special
restrictions on overall plant operation. Diagnostic routines,
interchangeable electronic cards or boards, and clear written
procedures shall be provided. Reliability, both software and
hardware, shall be incorporated into the system design. This
shall include redundancy, loop distribution, component
specifications and testing, and quality control to assure the
highest level of system reliability.
c.
Adverse Electrical Conditions: Equipment shall be capable of
operating as specified and without damage within the electrical
environment of the plant. This environment includes high-voltage,
high-frequency surges caused by electromechanical equipment,
energy coupled between conductors by capacitance and mutual
inductance, and imperfect grounds. Input and output isolation,
shielding, separation of circuits, surge suppression, or other
measures which may be required to meet these provisions shall be
provided. Inputs, outputs, and other connections shall meet the
surge to withstand requirements of IEEE C37.90.
2.7.5.2
System Design
The burner control system shall be compatible in all respects with the
boiler and auxiliary equipment. The system design shall meet the
requirements specified in NFPA 8501. The burner control system shall
incorporate a continuous purge of the furnace to insure that the boiler is
free of any accumulation of combustibles. The burner control system shall
also supervise the operation of the fuel-air equipment associated with the
pulverizer and fuel oil burners. The system shall accept operator commands
and, if the required permissives are met, perform the required operation.
Equipment shall be continuously monitored, and any deviation shall be
alarmed while the system either corrects the deviation or shuts down
equipment as necessary to avoid hazardous furnace conditions or equipment
damage. The system shall monitor the operation of the fuel equipment and,
if the equipment fails to respond to commands from the burner control
system, the equipment trip sequence shall be initiated. Indications shall
be provided to allow the operator to determine the equipment which
initiated a trip of fuel equipment. Tripped equipment shall be
successfully shut down before reset of the trip is permitted. The burner
control system shall include a fuel safety subsystem which shall include a
master fuel trip (MFT) system, ignitor fuel trip system, and pulverizer
mill trip systems. Each system shall include a hardwired relay which may
be directly operated from the operator insert panel. Inputs to the MFT
shall include, in addition to those associated with the burner control,
those that are required to provide overall boiler protection. Also, the
system shall interface with the combustion control system to position and
monitor devices for startup and shutdown which are normally modulated
during on-line operation. The burner control system shall be designed to
operate reliably and to minimize the number of false trips.
2.7.5.3
System Functional Requirements
a.
Operating Modes: The operator shall have the responsibility for
initiating the start and stop sequence listed below. Once
initiated, the burner control system shall automatically place the
mill or oil burner in service or remove it from service. The
steps, each of which requires operator initiation, are:
SECTION 15559A
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