Factors Affecting the Plant Capacity & Discipline of Engineering in a HydroPower Plant

Total Installed Capacity

- Head difference (vertical height) in water levels between two points

- Flow: the volume of water flowing through a area-cross section per unit time

No. of Units and Unit Capacity

• Accessibility and Transportation Limitations
• Availability of Technology
• Operation and Maintenance consideration

Power Developed by a Turbine

Pt = 9.81 x Q x H x η (KW)

Q = Discharge, m3/sec
H = Net Head, m
h = Efficiency of Turbine

ηtur = efficiency of turbine ( 89 % to 95 %)
ηgen = efficiency of generator (96% to 99%)

Discipline of Engineering in a HydroPower Plant

- Civil Engineering - Mechanical Engineering - Electrical Engineering

Civil Engineering further can be categories into Geological Engineering, Hydrological Engineering, Environmental Engineering and Structural Engineering.

Intake Structure and Water Conducting System

- Barrage/Dam - Diversion Structure - Intake Channel - Dislting Chamber - Tunnel - Surge & Drop Shaft - Pressure Shaft - Penstock - Powerhouse - Tail Race Structure

Mechanical Engineering aspect involve design , engineering, manufacturing, testing, selection of turbine and various equipment

Hydro-Mechanical, Power Generating Machines & Auxiliaries

- Intake Gates - Spillway Gates - Trash Rack - Disilting Valve/Gates - Penstock Protection Valve - Surge & Drop Shaft - Turbines & Auxiliaries - Main Inlet Valve - EOT Crane - Fire Protection System - Air Conditioning and Ventilation System - Cooling Water and Compressed Air System - Tail Race Gates

Electrical Engineering aspect involve design , engineering, manufacturing, testing, selection of generators, control systems, switchgear, transmission lines etc.,

Power Evacuating and Transmitting Systems

- Generators and Auxiliaries - Transformers - Control and Protection Systems - Switchyards - Circuit Breaker - Isolators - Current and Potential transformer - Communication Systems - Transmission Lines / Towers

Hydro Turbines

- What is a hydro Turbine

- What are the types of Hydro Turbines

- Bases of Classification of Turbine

- Working Principle of Turbine

- Components of Hydro Turbine

- Brief Comparison of Various Turbine

- Selection of Turbines

- Model Testing of Turbine

Get answers of above quistions in my next posts.

Components of a HydroPower Plant..3

Power House

Power House is a building to house the turbines, Generators and other accessories for operating the machines.

Components of Power House

A. Mechanical Component

Distributor/Spiral Casing- a casing or housing used to distribute the water equally all along the periphery of runner.

Spherical valve or Main Inlet Valve- Valve used to isolate the turbine or machine from water incase non-availability of water for generation or maintenance

Turbine; a hydromachine used to convert the hydraulic energy to mechanical energy

EOT Crane(Electric Overhead Crane); used to lift the equipment of the power house viz., rotor (heaviest component in the power station), stator, shafts, runner and other equipment

B. Electrical Component

Generator; machine used to convert the mechanical energy into electrical energy

Transformers; to step up the generation voltage upto the capacity of grid

Switchyard; is the central protection and metering of the outgoing feeders after stepping up of system voltage using transformer (usually consist of Circuit Breakers, Isolators, disconnect switch, Current transformer, Potential transformer, lighting arrestors etc)

Circuit Breakers: to disconnect the system in case of faults vis-à-vis short circuit, over voltage, under voltage, under frequency, distance faults etc

Disconnect switch/Isolators: to open the circuit as & when desired to take up the system for maintenance

Current Transformer: to step down the system current to the level of 1A/ 5A as the case may be. Used for current measurement and power measurement

Potential Transformer: for Power and voltage measurement

Communication system: consist of wave trap and PLCC for data transfer through power lines.

Transmission lines: using transmission line tower the power is transferred from the generating station to the nearest grid (of desired capacity) General rating of the lines are 11kV ,33kV, 66kV, 132 kV, 220 kV, 400 kV, 750/800 kV.

C. Power House Auxiliaries

Cooling Water system: used to supply the cooling water to Generator air coolers, Turbine bearing, Generator bearing, transformer cooling etc.,

Compressed Air System: used to supply compressed air to various turbine and generator auxiliaries for rotor lifting, generator brakes, service air etc.,

De- watering System: used to de-water the powerhouse in case of seepage, maintenance etc., also used for de-watering the tunnel, penstock.

Air conditioning and ventilation: used to maintain the normal working temperature inside the control room and powerhouse building for efficient working of equipment and operating staff.

Fire protection and detection systems this system is used to protect each Generating equipment and its auxiliaries of the powerplant against the fire hazards. Also, for insurance coverage this system is must and TAC (Terrific Advisory Committee) norms has to be follow for his approval.

Drainage system: used to drain water from powerhouse used for cleaning, water close-let, drinking water etc.

Components of a HydroPower Plant..3

Power House

Power House is a building to house the turbines, Generators and other accessories for operating the machines.

Components of Power House

A. Mechanical Component

Distributor/Spiral Casing- a casing or housing used to distribute the water equally all along the periphery of runner.

Spherical valve or Main Inlet Valve- Valve used to isolate the turbine or machine from water incase non-availability of water for generation or maintenance

Turbine; a hydromachine used to convert the hydraulic energy to mechanical energy

EOT Crane(Electric Overhead Crane); used to lift the equipment of the power house viz., rotor (heaviest component in the power station), stator, shafts, runner and other equipment

B. Electrical Component

Generator; machine used to convert the mechanical energy into electrical energy

Transformers; to step up the generation voltage upto the capacity of grid

Switchyard; is the central protection and metering of the outgoing feeders after stepping up of system voltage using transformer (usually consist of Circuit Breakers, Isolators, disconnect switch, Current transformer, Potential transformer, lighting arrestors etc)

Circuit Breakers: to disconnect the system in case of faults vis-à-vis short circuit, over voltage, under voltage, under frequency, distance faults etc

Disconnect switch/Isolators: to open the circuit as & when desired to take up the system for maintenance

Current Transformer: to step down the system current to the level of 1A/ 5A as the case may be. Used for current measurement and power measurement

Potential Transformer: for Power and voltage measurement

Communication system: consist of wave trap and PLCC for data transfer through power lines.

Transmission lines: using transmission line tower the power is transferred from the generating station to the nearest grid (of desired capacity) General rating of the lines are 11kV ,33kV, 66kV, 132 kV, 220 kV, 400 kV, 750/800 kV.

C. Power House Auxiliaries

Cooling Water system: used to supply the cooling water to Generator air coolers, Turbine bearing, Generator bearing, transformer cooling etc.,

Compressed Air System: used to supply compressed air to various turbine and generator auxiliaries for rotor lifting, generator brakes, service air etc.,

De- watering System: used to de-water the powerhouse in case of seepage, maintenance etc., also used for de-watering the tunnel, penstock.

Air conditioning and ventilation: used to maintain the normal working temperature inside the control room and powerhouse building for efficient working of equipment and operating staff.

Fire protection and detection systems this system is used to protect each Generating equipment and its auxiliaries of the powerplant against the fire hazards. Also, for insurance coverage this system is must and TAC (Terrific Advisory Committee) norms has to be follow for his approval.

Drainage system: used to drain water from powerhouse used for cleaning, water close-let, drinking water etc.,

Component of a HydroPower Plant..2

Intake Structure

Storage Reservoir: Constructed by building a dam/barrage across the river.

Escape structure or spillway: to allow the excess water to pass.

Diversion structure: are to divert the water for the taking it for power generation

Desilting basin: to remove the silt

Trash Rack: to prevent the debris, wooden blocks, stones etc., entering into the power house.

Gates: Intake gates, spillway gates, stoplogs etc., to regulate the flow

Water Conductor System

Power Canal: a small water channel/duct used to take the water upto the tunnel intake

Tunnel: a underground water conducting passage.

Surge Shaft or Surge Tank: a vertical water storage structure used to store water in case of emergency (prevent water hammer)

Drop shaft a vertical underground water conducting passage

Pressure Shaft a tunnel with high pressure of water used a water conducting passage.

Penstock: a large diameter steel/concrete pipes used to take water from the tunnel or forbay to powerhouse

Penstock Protection Valve (Butterfly Valve): used to isolate the water conducting system with the powerhouse in case of penstock repair or failure

Components of a HydroPower Plant

1. Intake Arrangement

• Storage Reservoir
• Diversion Structure or Spillway
• De-silting Basin
• trash Rack
• Gates

2. Water Conductor System

• Power Channel/Duct
• Tunnel
• Surge Shaft or Surge Tank
• Drop Shaft
• Pressure Shaft
• Penstock with Penstock Protection Valve (Butterfly Valve)

3. Power House

A. (Mechanical Component)

• Distributor / Spiral Casing
• Spherical Valve or Main Inlet Valve
• Turbine
• EOT Crane

B. (Electrical Component)

• Generator
• Transformer
• Switchyard
• Transmission Line

C. (Powerhouse Auxiliaries)

• Cooling water system
• Compressed Air System
• De-watering System
• Drainage System
• Air Conditioning System
• Control & Monitoring System
• Fire Protection System

The above components shall be discussed in details in forthcoming posts.

Types of Hydro Power Projects

• Run-Off the river Project

–Normal flow in a river which otherwise is un-utilised is used for generating power

–May require small storage facility

–Project based on stipulated dependability (90 %)

• Dam Storage based Projects

–releases of dam are passed through the generating units resulting in added benefits along with irrigation needs

–may cater as base load plant also

• Canal Based Projects

–utilises the drop (also sometimes called rapids) in a stretch of canal

–requires a diversion canal arrangement

• Pumped Storage Plants

–concept based on differential tariff structure

- peak time tariff and normal tariff

–Pumps water utilising power available (at lower tariff) during normal hours to a higher altitude

–utilising this storage, and generates power during peak time (charged at higher tariff)

• Tidal Projects

–utilises the energy of waves

Characteristics of Hydro-Power Plant

General :

•

• Renewable Energy Source, no fear of depleting fuel.

•

• Minimum expected availability - 95 %

•

• Environment Friendly

–

• No Pollution

–

• Requires minimum Submergence (for Run-off river projects)

–

•

• Multipurpose projects are possible i.e, irrigation, flood control, fishery, Tourism, etc. apart from Power Generation

•

• Smaller capacity project feasible (unlike economy of scale to be considered for thermal Project)

O & M aspects :

• Peak load Plant

• Part load operation is possible- with reasonable higher efficiency (in the range of 75-85 %)

• Low Operating and Maintenance Cost

•Requires very less auxiliaries system as compared to Thermal Power Projects.