POWER PLANT FAMILIARIZATIONBY

Er. Randhir KumarEr. Randhir Kumar

1 Intake

2 Penstock

3 Transformer

4. Power House

5. Generator

6. Runner

7. Draft tube

8. Tail Race

Principle of operation of a Hydro Station

The kinetic energy of falling water is first converted into mechanical energy in Turbine & then the mechanical energy is converted into electrical energy in Generator.

View of a Hydro Unit

Components

Generator

Turbine

Auxiliaries

Generator

CoolerRotor

Stator

Thrust Bearings

Air Gap

Stator Core

Made up of Silicon Steel laminated sheet with high permeability and low hystersis & eddy current losses

Stator Winding windings are copper conductors which carries the generated voltage.

Rotor It carries magnetic pole

& is revolved by turbine, resulting in power generation in stator.

Rotor

Pole

• Pole are mounted on rotor and It fulfills the need of a rotating magnetic field

Damper Bars

Dovetail keys

Core

Slip Rings

•Slip rings are installed on rotor to transfer the field current from the external excitation equipment to the field winding.

•The current flows through the stationary carbon brushes to the rotating slip rings, through insulated bars mounted in the hollow shaft and to the pole coil connections.

Guide Pads

To restrict the radial movement of machine.

GENERATOR

Segmented type guide bearing assembly

Thrust Bearing carries the whole weight of the machine.

Thrust Bearing high pressure lubrication port

Thrust Bearing

H S Lubrication system to safeguard thrust pads during starting & stopping of machine.

Bearing Pad Arrangement

Thrust Pad

H SLub Oil

Guide Pad

COoler

Cold Water

Hot Water

Oil

GENERATOR

TURBINE

Classification

Types of Turbine Types of Turbine

Kaplan Kaplan FrancisFrancis PeltonPelton

Medium & lower head up to 80 m when discharge& load vary widely

Medium & lower head up to 80 m when discharge& load vary widely

Medium & high Heads in the rangeof 30-550m, turbinedischarge varyingin acceptable limit

Medium & high Heads in the rangeof 30-550m, turbinedischarge varyingin acceptable limit

Heads greater than400m varying head,discharge and load conditions

Heads greater than400m varying head,discharge and load conditions

CLICK

Kaplan Runner

In a Kaplan runner blade angle varies with changing position of guide vanes. The runner blade servomotor is installed between themain turbine shaft and the generator shaft or inside the runner hub .

Oil Pipe line inside shaft

Hub

Cone

Runner Servomotor

PELTON FRANCIS

Spiral Casing

Guide Vane

Servomotor

Runner

Shaft Seal

Spiral Casing

Water from penstock enters the spiral casing which makes equal water thrust at each guide vane

Stay Vane

Spiral Casing

Stay Ring

Stay Vane

Guide Vane

Turbine

The wicket gate operating mechanism is installed with eccentric pins between the gate operating ring and each wicket gate to allow individual adjustment of wicket gate openings. Shear pins with carefully calculated size are provided with an operating mechanism. A pin will shear, should a wicket gate become blocked, and the remaining gates can be operated as required.

WICKET GATES AND OPERATING MECHANISM

REGULATING RING

Penstock Gate / MIV

Penstock Gate

MIV

• Brake

• H S Lub

• OPU system

• Cooling water

• Drainage , Dewatering

Some other auxiliaries

Practical braking speed 25-30% of rated speed

Brake

Air for BrakeOil for Jack

Rotating Machine

Oil Pressure Unit Supply pressurized oil to servomotor for opening or closing of guide vanes under the command of governor.

To system

oilairAir inlet

Cooling Water

For cooling of Generator Stator Windings

• Bearings

• Shaft Seals

• Transformer

• Fire Fighting

Open Loop Cooling water System

Booster Pump

Shaft Seal

Cooler(For Turbine

Bearings)

Oil Coolers(for Gen Bearings)

Air Coolers(For stator)

Transformer’sCoolers

Penstock

Tail Race

Close Loop Cooling Water System

Booster Pump

Shaft Seal

Cooler(For Turbine

Bearings)

Oil Coolers(for Gen Bearings)

Air Coolers(For stator)

Transformer’sCoolers

Cooling Pond

Tube Well

Sprinklers

Drainage System

Cooling pump floor

Turbine floor

Tail Pool Level

Water

Drainage pit

Water

POWER HOUSE

Water

Intake Level

Dewatering System

• The dewatering system is generally meant to dewater the penstock, spiral case and runner during their maintenance and inspection works.

EOT CraneEOT Cranes are used in powerhouses during commissioning, maintenance and repair of a hydro unit and their auxiliaries

Fire Extinguishing Systems

Types

•Automated sprinkler/spray protection •Hydrant Service•Hand appliances •Gaseous systems for control rooms

SprinklerHoses Portable Extinguisher

Operation of a Hydro Unit

• Pre Start Checks• Start Sequence• Synchronization• Stop Sequence• Monitoring during operation• Tripping • Emergency Handling

Pre Start Checks

Many of the start checks may be built up in the

starting interlocks and starting sequence. The

abnormality if any, will appear in MMI display

and “Unit ready to start” indication does not

appear. The list of activities/checks varies from

station to station.

ROTOR

TurShaft

Pole

CoolerIn

Gate

DTGate

GV

GV

Water

Gen Shaft

PoleStator Winding

GGB

Thrust Pad

CoolWater

Hotwater

HS LUB

cooler

Water

TRCM

Oil

DC Excitation

Restore AC & DC supply to auxiliaries

Reset relayOpen Draft Tube GateBrake releasedCooling chargedUnit ready to startOpen Intake gateH S Lub startOpen GVMachine start rolling100% speedVoltage Build up

UnitReady

ToSynchronize

START SEQUENCECheck PTW

TRANSFORMER

11 KV220KV

Synchronization

Rotor

Rotor Pole DC excitation by closing FCB

Trans

Transmission line

Close CB when V, F & Ph matches

CB

Stator

+ _

11KV 220KV

Monitoring during operation

Operate machine as per schedule & water level• Attend any alarm appearing in control room• Temperature of bearings/stator/transformer• Cooling water flow • Leakage water level in turbine pit• Operation of drainage pumps.• Generator Voltage and reactive Power flow.• Machine vibrations.• Abnormal sound from the machine.• Fill up hourly log sheet

Stop Sequence

Reverse to start sequence

Tripping of Machine on Fault

Stop machineStop machineNote down relayNote down relayInform Maintenance staffInform Maintenance staff

Emergency Handling

Increase in water level inside Power House

• Raise Alarm.• Intimate Power Station Incharge.• Try to stop the source of leakage water.• If the leakage is from the machine immediately close the intake gate after

opening the generator circuit breaker and giving stop command to the machine.

• Ensure that Power Supply to Drainage & Dewatering pumps is not shut down.

• Run the available drainage / dewatering pumps or any other available pumps to pump out the water.

Emergency Handling

Fire

• Raise Alarm.• If fire is in the machine or Transformer give stop command.

• Release CO2 or water through fire protection system .• Intimate fire station.• Inform Power Station authority• Try to isolate other equipment from the source of fire.

Thank You.