The Trishuli Hydropower Project is a 21 MW hydropower plant located 70 km from Kathmandu along the Trishuli River in Nuwakot, Nepal. It was constructed in 1967 with an installed capacity of 21 MW from 7 units of 3 MW each. It was later upgraded in 1995 to its current capacity of 24 MW from 6 units of 3.5 MW and 1 unit of 3 MW. The plant utilizes a 51.4 m maximum head from the Trishuli River, which has an average annual flow of 45.66 cubic meters per second. While it was one of Nepal's oldest hydropower plants, it continues operating through upgrades but still faces issues like silt accumulation and lack of

1. TRISHULI HYDROPOWER VISIT
Presented by:
Surendra purbey(070/BEL/346)
Kamal singh tharu(070/BEL/314)
Sanjit kumar singh(070/BEL/337)
Sadanand kumar yadav(070/BEL/330)
Binay aale (070/BEL/3 )
Mukesh bhatt(070/BEL/3 )
Aashis karki (070/BEL/243 )

2. INTRODUCTION

3. TRISHULI NUWAKOT

4. GENERAL 0VERVIEW
Located at 70 km north-west of Kathmandu at Trishuli, Nuwakot
Constructed on Trishuli river
Installed capacity 21 MW in 1967 AD consisting of 7 units each of 3 MW
Upgraded to 24 MW in 1995 AD with 6 units each of 3.5 MW and
one unit of 3 MW
Developed By Government of India and Government of Nepal at a
Cost of INR 140 million
Head of station Baburaja Maharjan

5. SAILENT FEATURES
Maximum net head 51.4 m
Average annual flow 45.66 m^3/s
Length of Dam 139.6 m
Length of Waterway 4,792 m
Penstock 71.66 m & 2.3 m , 3Nos., steel
(length &dia.) 89 m & 1.5 m, 1Nos., steel
No. of Bridge 4
Catchment area 2600 sq km
Design generation 163 GWh annually

6. GENERATOR
Rated Output 3889 KVA
Rated Voltage 6.6 KV
Rated Frequency 50 Hz
Power factor 0.9
Power Transformer 5 MVA , 6.6/66 KV Single phase,6 Nos
Transmission Line 66 KV 27.6 km , Double circuit
66 KV 5 km ,Single circuit
TURBINE
Number and type 7, Francis
Rated Discharge 7.8 m^3/s
Rated Output 3620 kw
Rated Speed 500 rpm

7. CIVIL PART

8. WATER RETAINING STRUCTURE WITH SIDE
CHANNEL SPILLWAY

9. SIDE INTAKE

10. LIFT GATE WITH GEAR ROPE ELECTRIC DRIVE

11. TRAPEZOIDAL OPEN CHANNEL SYSTEM

12. OVERHEAD FLOW OVER RIVER
o Flow is diverse through residential area with two bridge type canal.

13. SETTLING BASIN (DECENDER)
oIt removes sediment load up to 0.2mm diameter.
oThe greater basin area & lower the through velocity the smaller the particles can settle down.
oOne traits for this case is being used as picnic spot area.

14. RESERVOIR
o We can notice problem of high silt.

15. FOREBAY
oEntry point for three penstock pipes
oStructure being lies on highway of headquarter

16. PENSTOCK PIPES
o Each 3 pipes serves for two units while last pipe feed single unit

17. MECHANICAL PART

18. TURBINE GENERATOR SETS

19. o Number of blades = 13 Inlet diameter = 1080 mm Throat diameter = 1100 mm
RUNNER

20. WICKET GATE

21. GOVERNER

22. SPIRAL CASING

23. INLET VALVE BY-PASS VALVE

24. DRAFT TUBE

25. TAILRACE
Here centered pipe is used to discharge leakage water (dewatering)
Initially tailrace discharge is mixed to trisuli itself
Now it is used for devighat power plant

26. ELECTRICAL PART

27. GENERATORS
parameter Unit 1-3 Unit 4-7
Original designer Rade koncar Fuji electric
Rated output 3500kw(+10% overload) 3500kw(+10% overload)
Rated capacity 3889 KVA 3889 KVA
Rated voltage 6.6KV 6.6KV
Stator connection 2Y 1Y
Rated current 340A 340A
Runaway speed 925 r.p.m 925 r.p.m
Stator winding resistance (per
phase)
0.10064 ohm @ 77°C 0.10064 ohm @ 77°C
Rotor winding resistance (per
phase)
0.1272 0.1159
Full load efficiency 96.79% 96.79%

28. SYNCHRONIZING PROCESS
Manual operation
Unit is connected to grid when its voltage and real power match system parameters
respectively

29. POWER FREQUENCY CONTROL
The regulator must designed to be insensitive to fast random
changes, otherwise the system will prone to hunting resulting in
excessive wear & tear of rotating machines & control
equipment.

30. EXCITATION SYSTEM
PLC or Human machine interface(HMI) is used to control excitation automatically and remotely.

31. STATIC EXCITATION SYSTEM
Field current:
At no = 157-164.7A @ 77V
At full load = 290-304.2A
At 110% rated load = 306-320A

32. PLC
Programmable Logic Controller is a user friendly, microprocessor specialized computer that
carries out control functions.
oMonitor crucial process parameters and
adjust process operations accordingly.
oCan be programmed, controlled and
operated by a person unskilled in operating
computers.
oPLCs are used in the substation to manage
transformers, voltage regulation, automatic
transfer schemes, custom/automatic reclosing
schemes, automatic service restoration,
remote control, system diagnostics
maintenance

33. SWITCHING PANELS
o Double for double bus bar system.

34. INDOOR HV VCB

35. CONTROL SYSTEM

36. CONTROL ROOM
oEach unit have its own control set.
oAt least one technical must be here to monitor whether generation and other operation is
within limit.

37. TRANSFORMER CONTROL & RELAY PANEL

38. GENERATOR PROTECTION PANEL

39. DATE U1 U2 U3 U4 U5 U6 U7 TOTAL(
MW)
8/21 3 2.5 3 1 3 3 3 18.5
8/22 3 3 3 1 3 3 3 19
8/23 2 3 3 1 3 3 3 18
8/24 3 2 3 1 3 3 3 18
8/25 3 2 3 1 3 3 3 18
GENERATION DATA OF 8/21 TO 8/25

40. STATION ANNUNCIATOR PANEL
o It indicates which of several electric circuits has been activated.

41. RECORDER PANELS

42. TRANSDUCER PANELS

43. BATTERY ROOM
oThe control panels and relays require DC supply of 220V.
oNi-Cd batteries are used due to their advantages like low maintenance , longer life
(15-25 years).
oEach cell is of 2V and 6Ah capacity.
o55 cell is connected to 110V charging system.
oNormally charging panel delivers load & give trickle charging to Battery bank
oworks on Auto and Manual mode.

44. FIRE PROTECTION
o A new fire detection and protection system was installed with complete Halogen gas fire,
portable fire extinguishers and fire hose reels and fire hydrants for total protection of power
house.

45. SWITCHYARD

46. oJunction of four areas network
oBalaju-1 and balaju-2 by double circuit transmission line (27.6Km)
oChilime and devighat (5Km) by single circuit
oAlso distribute power to local area
SUBSTATION

47. SINGLE LINE DIAGRAM

48. TRANSFORMERS
oSix single phase power transformers of rating 5 MVA 6.6/66 kv
oOne 3 phase distribution transformer of rating 10 MVA 6.6/11 kv for local distribution

49. COOLING AND FIRE EXTINGUSHER
oCooling pipe are run along all transformers
oOperate when transformer are overloaded or any abnormal conditions

50. INSTRUMENTATION TRANSFORMERS
66 kv CT 66 kv PT

51. SF6 CIRCUIT BREAKER

52. BUS COUPLER
o Coupling is done when one bus bar fails which removes interruption to feeder.

53. SURGE PROTECTION
LIGHTNING PROTECTOR ROD GAP ARRESTER

54. CONCLUSION

55. SPECIAL FEATURES
• One of the oldest HPP but still operating well
• Lies on headquarter of Nuwakot
• More number of units making it more efficient
• 3 single phase transformers combine to make three phase has its
own advantage
• Tailrace utilize for another HPP

56. PROBLEMS
• Small area of the settling basin so the sand does not settle properly in the basin.
• Problem in diversion system and intake construction.
• There is no SCADA system in use.
• The amount of silt accumulated in the reservoir is excess.
• Weir and tear on the runner due to silt.
• Manual synchronizing and Governing system.
• The settling basin should be upgraded.
• The direction of the flow of water should be managed at diversion weir.
• The SCADA system should be maintained as soon as possible.
• The number of instrument to clean silt should be increased.
• Governing and overall system should be upgraded to digital.
RECOMMENDATIONS

58. • www.nea.org.np
• www.google.com
• Handbook of
Trishuli hydropower
Project
• Trishuli Upgrading
File
REFERENCES