Advantages and Disadvantages

Hydro Power PlantSubject: Fluid Power EngineeringBVM Engineering College

Enrollment No.

Name

120070119001

Ketan Laiya

120070119084

Vipul Vasava

Prepared by:

Guided by Prof. M.J.Zinzuvadia

Index

Introduction

Components of Hydro Power Plant

Classification

Advantages and Disadvantages

Impact of jet

force exerted on stationary flat plate normal to jet

force exerted on stationary inclined plate to jet

Introduction

In nature, a flowing stream of water dissipates throughout thelength of the watercourse and is of little use for power generation.Electricity from water is usually referred to as Hydro-Power, where theterm ‘hydro’ is the Greek word for water and hydropower is the energycontained in water. It can be converted in the form of electricity throughhydroelectric power plants. To make the flowing water do work usefullyfor some purpose like power generation (it has been used to drive waterwheels to grind grains at many hilly regions for years), it is necessary tocreate a head at a point of the stream and to convey the water through thehead to the turbines which will transform the energy of the water intomechanical energy to be further converted to electrical energy bygenerators.

(1) DamDams are structures built over rivers to stop the water flow and form areservoir. The dams collect water during the rainy season and stores it, thusallowing for a steady flow through the turbines. The dams should be water-tight and should be able to withstand the pressure exerted by the water on it.The height of water in the dam is called head race.(2) SpillwayA spillway is a way for spilling of water from dams. It is used to provide for therelease of flood water from a dam. It is used to prevent over toping of the damswhich could result in damage or failure of dams. The uncontrolled spillwaysstart releasing water upon water rising above a particular level. But in case ofthe controlled type, regulation of flow is possible.

(3) Penstock and TunnelPenstocks are pipes which carry water from the reservoir to the turbines insidepower station. They are usually made of steel and are equipped with gatesystems. Water under high pressure flows through the penstock. It is usedwhen an obstruction is present between the dam and power station such as amountain.

Components of Hydro power plant

(4) Surge TankSurge tanks are tanks connected to the water conductor system. Itserves the purpose of reducing water hammering in pipes which cancause damage to pipes. The sudden surges of water in penstock is takenby the surge tank, and when the water requirements increase, itsupplies the collected water thereby regulating water flow and pressureinside the penstock.

(5) Power StationPower station contains a turbine coupled to a generator (see the crosssection of a power house on the left). The water brought to the powerstation rotates the vanes of the turbine producing torque and rotationof turbine shaft. This rotational torque is transferred to the generatorand is converted into electricity.

The used water is released through the tail race. The differencebetween head race and tail race is called gross head and by subtractingthe frictional losses we get the net head available to the turbine forgeneration of electricity.

Typical components of a hydroelectric plant consist of the following:

1. Structure for water storage and/or diversion, like a dam or a barrage.

2. A head-race water conveying system like a conduit (penstock) or an openchannel to transport water from the reservoir or head-water pool up to theturbines.

3. Turbines, coupled to generators

4. A tail race flow discharging conduit of open channel that conveys the waterout of the turbine up to the river.

(a)

(b)

Classification of hydro power plants:

Run of river without storage

Run of river with storage suitable to balance diurnal variation in powergeneration

Pump Storage plant

Tidal power development plant

According to height :

Low head <30m

Medium head 30m to 300m

High head >300m

According to their operating functions as follows:

1. Base load power plant: A power station operating continuously at aconstant or nearly constant power and which operates at relating highload factors. It caters to power demand at base of the load curve.

2. Peak load power plant: A power station that is primarily designed forthe purpose of operating to supply the peak load of a power system.This type of power station is also, therefore, termed as ‘Peaking station’.

According to plant capacity hydropower plants can also be classified as:

1. Midget plant: up to 100KW

2. Low-capacity plant up to 1,000KW

3. Medium capacity plant up to 10,000KW

4. High capacity plant > 10,000KW