TRISHULI HYDROPOWER VISITPresented by:

Baikuntha Poudel(070/BEL/208)Ishwor Singh(070/BEL/219)

Kishor Ghimire(070/BEL/222)Khagraj Subedi(070/BEL/221)

Ramesh Adhikari(070/BEL/233)Suman Sharma(070/BEL/242)

Sunil K.C.(070/BEL/243)

INTRODUCTION

TRISHULI NUWAKOT

GENERAL 0VERVIEW

Located at 70 km north-west of Kathmandu at Trishuli, NuwakotConstructed on Trishuli river Installed capacity 21 MW in 1967 AD consisting of 7 units each of 3 MWUpgraded to 24 MW in 1995 AD with 6 units each of 3.5 MW and one unit of 3 MWDeveloped By Government of India and Government of Nepal at a

Cost of INR 140 millionHead of station Baburaja Maharjan

SAILENT FEATURESMaximum net head 51.4 mAverage annual flow 45.66 m^3/sLength of Dam 139.6 mLength of Waterway 4,792 mPenstock 71.66 m & 2.3 m , 3Nos., steel (length &dia.) 89 m & 1.5 m, 1Nos., steelNo. of Bridge 4Catchment area 2600 sq kmDesign generation 163 GWh annually

GENERATORRated Output 3889 KVARated Voltage 6.6 KVRated Frequency 50 HzPower factor 0.9Power Transformer 5 MVA , 6.6/66 KV Single phase,6 NosTransmission Line 66 KV 27.6 km , Double circuit 66 KV 5 km ,Single circuit

TURBINENumber and type 7, FrancisRated Discharge 7.8 m^3/sRated Output 3620 kwRated Speed 500 rpm

CIVIL PART

WATER RETAINING STRUCTURE WITH SIDE CHANNEL SPILLWAY

SIDE INTAKE

LIFT GATE WITH GEAR ROPE ELECTRIC DRIVE

TRAPEZOIDAL OPEN CHANNEL SYSTEM

OVERHEAD FLOW OVER RIVERo Flow is diverse through residential area with two bridge type canal.

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.

RESERVOIRo We can notice problem of high silt.

FOREBAYoEntry point for three penstock pipesoStructure being lies on highway of headquarter

PENSTOCK PIPESo Each 3 pipes serves for two units while last pipe feed single unit

MECHANICAL PART

TURBINE GENERATOR SETS

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

RUNNER

WICKET GATE

GOVERNER

SPIRAL CASING

INLET VALVE BY-PASS VALVE

DRAFT TUBE

TAILRACEHere centered pipe is used to discharge leakage water (dewatering)Initially tailrace discharge is mixed to trisuli itselfNow it is used for devighat power plant

ELECTRICAL PART

GENERATORSparameter Unit 1-3 Unit 4-7Original 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%

SYNCHRONIZING PROCESSManual operationUnit is connected to grid when its voltage and real power match system parameters respectively

POWER FREQUENCY CONTROLThe 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.

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

STATIC EXCITATION SYSTEMField current:At no = 157-164.7A @ 77VAt full load = 290-304.2AAt 110% rated load = 306-320A

PLCProgrammable 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

SWITCHING PANELSo Double for double bus bar system.

INDOOR HV VCB

CONTROL SYSTEM

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

TRANSFORMER CONTROL & RELAY PANEL

GENERATOR PROTECTION PANEL

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

STATION ANNUNCIATOR PANELo It indicates which of several electric circuits has been activated.

RECORDER PANELS

TRANSDUCER PANELS

BATTERY ROOMoThe 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 bankoworks on Auto and Manual mode.

FIRE PROTECTIONo 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.

SWITCHYARD

oJunction of four areas networkoBalaju-1 and balaju-2 by double circuit transmission line (27.6Km)oChilime and devighat (5Km) by single circuitoAlso distribute power to local area

SUBSTATION

SINGLE LINE DIAGRAM

TRANSFORMERSoSix single phase power transformers of rating 5 MVA 6.6/66 kvoOne 3 phase distribution transformer of rating 10 MVA 6.6/11 kv for local distribution

COOLING AND FIRE EXTINGUSHER oCooling pipe are run along all transformersoOperate when transformer are overloaded or any abnormal conditions

INSTRUMENTATION TRANSFORMERS66 kv CT 66 kv PT

SF6 CIRCUIT BREAKER

BUS COUPLERo Coupling is done when one bus bar fails which removes interruption to feeder.

SURGE PROTECTIONLIGHTNING PROTECTOR ROD GAP ARRESTER

CONCLUSION

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

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

• www.nea.org.np• www.google.com• Handbook of

Trishuli hydropower Project• Trishuli Upgrading

File

Thank you !!!

REFERENCES