The document summarizes the internship experience of three students at the Ashuganj Power Station Company Ltd (APSCL) in Bangladesh. APSCL generates about 15% of the country's power using 9 generating units with a total installed capacity of 777 MW and de-rated capacity of 731 MW. During their two-week internship, the students visited different sections of the power plant including the generator, control room, substation, and received mentoring from engineers. They observed the power generation process involving natural gas, steam turbines, and generators. The internship provided hands-on learning but was limited by the short duration and harsh temperatures in sections like the generator room.

1. PRESENTED BY
MAHMUDUR RAHMAN RANA
2008-2-80-007
SHAMSUL ARIFIN CHOWDHURY
2008-1-80-029
ARIF AHMED
2008-1-80-031
Thanks to our instructors at APSCL
•Engr. Rokonuzzaman and
•Engr. Kamruzzaman

2.  Ashuganj Power Station Company Ltd. (APSCL) is the second largest power station in
Bangladesh.
 Ashuganj Power Station fulfills about 15% of power requirements of the country.
 Installed Capacity : 777 MW.
 Present De-rated capacity: 731MW.
 Number of Generating Units: 9 (6 Steam Turbine + 2 Gas Turbine+ 1 Gas Engine)
 Fuel used: Natural Gas Supplied by Titas Gas Transmission & Distribution Co. Ltd
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3. 3
Date Section Time Mentor
24-08-2012 Visiting APSCL 8.00am- 4.00pm Md. Rokon-Uz-Zaman
25-08-2012 Generator Section 8.00am- 4.00pm Md. Rokon-Uz-Zaman
26-08-2012 Generator Section 8.00am- 4.00pm Md. Rokon-Uz-Zaman
27-08-2012 Winding Shop 8.00am- 4.00pm Md. Rokon-Uz-Zaman
28-08-2012 Control Unit 1 and 2 8.00am- 4.00pm Md. Rokon-Uz-Zaman
29-08-2012 Control Unit 3 and 4 8.00am- 4.00pm Md. Rokon-Uz-Zaman
30-08-2012 Control Unit 5 8.00am- 4.00pm Md. Rokon-Uz-Zaman
31-08-2012 Combined Cycle Power Plant 8.00am- 4.00pm Md. Rokon-Uz-Zaman
01-09-2012 Battery Room 8.00am- 4.00pm Md. Rokon-Uz-Zaman
02-09-2012 Generator Section 8.00am- 4.00pm Md. Rokon-Uz-Zaman
03-09-2012 Generator Section 8.00am- 4.00pm Md. Rokon-Uz-Zaman
04-09-2012 Boiler Section 8.00am- 4.00pm Md. Rokon-Uz-Zaman
05-09-2012 Steam Turbine Section 8.00am- 4.00pm Md. Rokon-Uz-Zaman
06-09-2012 Water Treatment Plant 8.00am- 4.00pm Md. Rokon-Uz-Zaman
07-09-2012 Substation 8.00am- 4.00pm Md. Rokon-Uz-Zaman

4. Parts of a Generator
 Stator.
 Rotor.
 Armature.
 Carbon brushes.
 Collector Slip Rings.
Figure: The generator system(Unit 1)
Generator is a device that converts
mechanical energy into electrical energy
as the output.
Figure: Carbon brushes
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5. At APSCL three types of excitation systems are used. These are:
AC Excitation System: Used in steam turbine 1and 2.
Static Excitation System: Used in steam turbine 3, 4 and 5.
Brushless Excitation System: Used in gas turbine 1and 2.
Excitation
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6. At APSCL, there are three control rooms.
 Unit 1 and 2 are operated by control room 1.
 Unit 3 and 4 are operated by control room 2.
 Unit 5 is operated by control room 3.
Figure: Control room 1 Figure: Control room 2 Figure: Control room 3
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8. At APSCL two types of relay is used. There are:
 Electrical relay:
 Use for protection at units 1 and 2.
 Tripping condition manually.
 Larger size.
 Electronic relay:
 Microcontroller based relay.
 Very effective and fast to trip the circuit.
 Use for protection at units 3, 4 and 5.
 Protection of generator:
 Generator differential protection.
 Stator over-heating protection.
 Rotor temperature protection.
 Rotor earth fault protection.
 Over frequency protection.
Figure: Electrical relay
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9.  Moisture in the generator winding.
 Over-voltage.
 Under frequency.
 Vibration.
 Local overheating.
 Excessive bearing temperature.
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10.  At APSCL two kinds of battery are used.
 Led acid battery.
 NI-CD battery.
 Features of series connected battery
 No of battery: 184
 Each sell voltage: 1.2V
 Total voltage: 220V
 Battery Maintenance test
 Breathing test.
 Liquid level test.
 Specific gravity test. Figure : Series connected battery
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11.  Megger test.
 Mechanical speed checking.
Water cooling system .
Air cooling system.
Hydrogen cooling system.
Figure: Motor winding and repair section
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12. Screening Sedimentation Filtration Clear Water
River
Water
ScavengerCationAnionMixed Bed
Demineralized
Water
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13. River
Water
WTP
Feed
Water
Pump
LP1, LP2 Drum
Economizer
Boiler
Flow
Gas
HP1, HP2
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14.  Boiler
Evaporation capacity :
270 t/hr (ST-1,2)
500.4 t/hr (ST-3,4,5)
Efficiency: 90 % (ST-1,2)
86.8% (ST-3,4,5)
 Furnace
Temp: 1200-1500°C
 Super Heater
 Pressure of steam:
93 bar (ST-1,2)
138.5 bar (ST-3,4,5)
 Re-Heater
 Condenser
 Feed Water Heater: LP, HP
Figure: Steam power plant
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15. Gas Turbine Section
 Compressor
 Combustion Chamber
 Gas Turbine
 Diesel Engine
Figure: Combustion Chamber Figure: Diesel Engine
Steam Turbine
Flue Gas Temp.: 1010°C
Exhaust Gas Temp. : 569°C
Figure: Steam Turbine
Steam Turbine Section
 Exhaust gas from gas turbine is used to produce steam.
Evaporation capacity : 126 t/hr
Steam Pressure: 39 bar
Steam Temp. : 490°C
Turbine speed : 3000 rpm
RPM of
Turbine
(GT-1,2)
Situation
0 rpm Diesel start
750 rpm Ignition inside comb.
chamber
1800rpm Diesel off
2300 rpm Excitation on
3000 rpm At no load condition
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16. Bus Bar
 At APSCL Double bus-bar
arrangement in used
Outgoing Bus
 132 KV Bus
 230 KV Bus
A 6.6 KV incoming Bus is also
present in APSCL
Outgoing Feeder
132 KV
Shajibazar-3
Shajibazar-1
Shajibazar-2
Ghorashal-1
Ghorashal-2
Kishoregonj-1
Kishoregonj-2
230 KV
United 50MW Rental
AGRECO 80MW Rental
Comilla-I
Comilla-II
Ghorashal-1
Ghorashal-2
Substation
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17. Step up transformer
In APSCL we have seen three types of transformer.
Current Transformer Potential Transformer
 Used for measuring
the current in electric
equipment
 Connected in series
 Reduce current when measuring
 Used for measuring
the voltage in the circuit
 connected in parallel
 Rated voltage – 132KV &
230KV
 Rated frequency – 50Hz
 Used to increase the voltage
 Secondary part is connected
to bus bar
Substation
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18. Lightning Arrester Circuit Breaker
SF6 CB
Oil CB
A lightning arrester is a
device used on
electrical power system to
protect the
insulation system and other
equipment from the damaging
effect of lightning
In electrical engineering,
an isolator is used
to make sure that
an electrical circuit
can be completely
de-energized for
service or maintenance
Isolator Lightning Arrester
Substation
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19.  Duration of 100 hours are not sufficient to gather all the knowledge.
 Generator section was too much hot. Temperature around 40°C - 45°C.
 Generator section was also too much noisy.
Recommendation
• Student must have a clear theoretical knowledge about a power station
before the internship.
• At the station anything should not be touched without permission because
this is high voltage power station.
• If any problem is faced to understand the relevant topics at the student
should ask the supervisor.
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20. Questions
?
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