Vol. 27
No. 4
CENTRE OF EXCELLENCE FOR
SIMULATORS ESTABLISHED
BHEL has recently established a state-of-the-art
Centre of Excellence for Simulators at its Corporate
Research and Development Division, at a cost of
Rs. 37.8 million. The Centre of Excellence not only
highlights the extant Power Plant Simulation
capabilities of BHEL, but would also play a vital role
in large-scale commercialization activity in this
advanced area. The Centre has the facility for
carrying out Dynamic Simulation Studies for
Combined-Cycle Cogen Plants and Thermal Power
Plants. In the recent past, many simulation studies
were executed commercially for various combinedcycle cogen plants.
December 2004
The Centre of Excellence features state-of-the-art
Pentium workstations, Itanium servers and a large
Video Display wall, to facilitate hands-on training for
up to five operators at a time, supplemented by an
attached lecture hall with a networked projection
facility for observing the plant operation.
The Virtual Power Plant model of the Centre is a
promising and ideal platform for testing and
evaluating the PADO (Performance Analysis
Diagnostics and Optimisation) software which is
emerging as a regular requirement for all the power
plants of NTPC. The Virtual Power Plant model also
facilitates testing of new and advanced control
schemes, like Automatic Plant Startup, adaptive and
fuzzy controls.
The Centre implements a typical 500 MW Thermal
Power Plant simulator, which is a total in-house
development based on the first-principles approach,
and supports a wide range of malfunctions covering
the entire plant operations.
In addition to the Operator Training Simulator
facility, the Centre is also equipped with Controller
Testing Simulator setup, for evaluating and tuning
the controllers based on ProControl and maxDNA
C&I platforms.
Besides meeting the training requirements of power
plant operation staff, the Centre also provides an
ideal platform for providing the required exposure on
plant operations, to the engineer trainees and
commissioning staff of BHEL.
The Centre of Excellence for Simulators
The above facility has already been put to use in
testing one such proposed advanced control scheme,
viz., Free Governor Mode Operation, aimed at
maintaining grid frequency at 50 Hz for obtaining
better quality of power. The concerned Steering
Committee comprising CEA, NTPC, BHEL &
PGCIL members, suggested that the proposed
scheme be checked on a simulator before
implementation. Accordingly, the effects of different
governor control schemes on plant parameters for
different frequency patterns were studied and the
scheme was finalized, using the simulator at the
Centre of Excellence. Thereafter, the scheme was
implemented at NTPC's Simhadri Power Plant.
BHELSCAN — A DIGITAL FLAME
SCANNER
BHEL has developed a digital flame scanner, BHEL
SCAN, for better and more reliable flame detection.
In BHELSCAN, advanced technology for flame
signal processing and discrimination/identification of
different flames, has been introduced, by redesigning the conventional flame scanner with a
totally fresh approach taking advantages of the
microcontroller technology. To overcome the usage
of independent flame scanners for different fuels like
coal and oil, a new integrated type flame scanner,
which can detect the flames of various fuels as a
single scanner, has been developed. The system can
be easily retrofitted with existing flame scanner head
assembly.
The flame scanner consists of scanner head
electronics and a control unit. The head assembly of
the scanner consists of a quartz lens for collection of
light signal and a fibre optic cable for transmission of
the light signal to the head electronics. In the head
electronics, a photo diode is used to convert the light
signal to electrical signal.
The electrical output of photo diode is amplified by a
log amplifier. The amplified signal is then
compensated for background radiation of the
furnace. The flame intensity component and flicker
component of the signal is separated and processed
for characteristic frequencies of coal and oil flames by
a microcontroller-based signal processing card. The
software ensures discrimination of different flames
through proper detection of characteristic flicker
frequency range of the flame.
Salient Features
• Digital Processing ensures reliability of flame
detection
• Improved accuracy and better response
• Digital display for various parameters
• 2 ½ digit LED display with display mode
selection by push button
• Protection EMI/RFI filter for power input
• Provided with serial communication interface
for communication with DCS
• Fault indication is provided for short circuit &
dark furnace.
BHELSCAN system configuration
B H E L V I S I O N 2 0 M —
M I C R O C O N T R O L L E R-B A S E D
E L E C T R O N I C WAT E R L E V E L
INDICATOR FOR BOILERS
Extensive research in level indication has culminated
in the introduction of electronic water level indicating
system based on conductivity principle.
BHELVISION 20M, developed by BHEL, works on
the above principle (difference in electrical
conductivity of steam and water). The proven
technology of BHELVISION 20M has been applied
for the critical application of drum water level
monitoring in utility and industrial boilers.
application. For large-scale demonstration of this
product, 24 solar geysers have been engineered,
and installed at the Executive Hostel Block of ASCI,
Hyderabad, for supplying hot water to the 93 hostel
rooms. One solar geyser of 100 lpd capacity has
been installed on the terrace connecting the four
bathrooms vertically located in the four-storeyed
building. The systems have been under continuous
operation since January 2004, supplying hot water
to the hostel rooms. ASCI has expressed satisfaction
with the performance of the solar geysers.
High water level leads to harmful water carryover to
turbine blades. On the other hand, low water level
leads to starvation in tubes leading to tube failures.
BHELVISION 20M system enables proper
monitoring of water level in boiler drum.
Salient Features
• Advanced microcontroller-based technology
• International certification by CSA
• 4-20mA analog output for level indication
• Electrode fault identification by flashing LED
• Group fault indication including indication for
abnormal conditions : water above steam/
steam below water.
• On-line simulation facility
• Detection of electrode and cable open or
short condition
• Fault in one channel not affecting other
channels
• Component level serviceability.
DISTRIBUTED HOT WATER SYSTEM
THROUGH 100 LPD SOLAR
GEYSERS ENGINEERED AND
INSTALLED
BHEL has developed and tested extensively solar
geysers of 100 lpd (litres per day) capacity using
thermo-syphon heat pipe principle, for domestic
Distributed hot water system installed at ASCI, Hyderabad
Normally, utilities of the above type are provided
with centralised large water heating systems with
long insulated hot water delivery lines. In
comparison, the individual solar geysers installed at
ASCI have eliminated lengthy water delivery lines,
reducing the heat losses and thereby enhancing the
performance of the system.
BHEL FURTHER IMPROVES ITS
a-Si DOUBLE-JUNCTION SOLAR
CELL MODULES
A process for large-area (2700 cm2), doublejunction amorphous silicon (a-Si) solar cell modules
was developed at Amorphous Silicon Solar Cell
Plant of BHEL, during 2001-2003. The power
output of these modules ranged from 14-17.5 W
corresponding to a maximum total area efficiency of
6.5%. Since then, various improvements have been
effected in these large-area solar cell modules. These
improvements have contributed to an increase of
~18% in the cell current which, in turn, has resulted
in raising the module output to 18-19W from
14-17.5 W. In addition, the cost of raw material has
reduced as the normal float glass used earlier as
substrate has been replaced by sheet glass which is
~ 40% less expensive.
BHELMHO — A STATE-OF-THE-ART
E L E C T R O N I C WAT E R L E V E L
SWITCH
BHEL has developed water level switch,
BHELMHO, based on the measurement of differing
electrical conductivity of water and no-water space,
without necessitating any density correction. This
results in accurate and reliable level detection,
rendering the BHELMHO a superior alternative to
the conventional mechanical float-type level
switches.
BHELMHO level switch has four electrodes which
sense the water level and provide indication through
the system's own dedicated circuitry and output
relays. A safe low excitation voltage is applied
between the insulated tip and the body of the sensing
electrodes. The sensor output is dependant on the
conductance of the cell formed by the electrode and
the body. It is compared with a reference value and
the electronic circuitry discriminates between nowater and water. In addition, the electronics is
capable of detecting the open and short fault
conditions of the sensing system.
Salient Features
• Replacement for float-type switch, with no
moving parts
• High reliability
• Wide choice of power inputs : 110V AC,
230V AC or 24V DC
• Dual power supplies for enhanced availability
• Square-type large LED display
• Self-diagnostics and fault indications
• Compact enclosure of IP55/IP65 protection
class
• Sensor (electrode) manufactured by BHEL,
thus ensuring prompt after-sales service.
Areas of Application in Power and Process
Plants
• De-aerator storage level
• HP & LP heater columns
• Main boiler drum level
• Blowdown tank level
• Main steam header drains
• Hot and cold reheat drains
• Turbine extraction drain
• Hot well alarms
• Generator coolant level
• Turbine casing drain.
Typical BHELMHO water level switch installation in HP heater
Issued quarterly by the Corporate Office, Bharat Heavy Electricals Limited, BHEL House, Siri Fort, New Delhi-110049, Website : http://www.bhel.com
Editor : P. Jagannathan. Associate Editor : D. Roy. Designed & Printed at NIKHIL OFFSET, New Delhi-110020. Phones : 26812316, 26810097, Telefax : 26810458
For Private Circulation only