Small-scale hydro is mainly run of river, so does not involve the construction of large dams and reservoirs.Small hydro power station are comprised of turbine generators and the structures necessary to channel and regulate the flow of water to the turbines.

THE POWER IN WATER

SMALL HYDRO SYSTEM COMPONENTS

HYDRO ENERGY PRODUCTION EQUIPMENT

THE POWER IN WATER

Water flows from high points to low points because of the force of gravity. There is energy embodied in the flow of water, and hydro-electric power systems capture some of the energy and convert it to electric power.

The power available in the a flow of water over a given interval depends on two factors: the vertical distance the water "falls" over the interval, measured in feet of meters, and the volume of the flow of water, measured in cubic feet or cubic meters per second.

IF a dam is constructed to block the flow of water, a river or stream may be channeled through turbines connected to electric generators to produce power. The power produced by the hydro-electric system is the product of three parameters: the distance the water falls fall from the intake to outlet, the volume of the flow of the water, and the efficiency of the turbine/generator equipment.

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SMALL HYDRO SYSTEM COMPONENTS

POWER HOUSE

The power house stores and protect all the power-producing equipment and control devices. These devices can be operated and monitored either on site or remotely.

FEEDER CANAL

Water flows down the feeder canal from the intake to the forebay .The canal is usually made of earth or concrete, and is fitted with a grating to keep out solid objects carried by the stream.

PENSTOCK

The penstock is a pipe connecting the forebay to the power house, It pressurizes the water and must be capable of withstanding high pressures, and is therefore usually made of steel

FOREBAY

The forebay is a tank that holds water between the feeder canal and the penstock. It must be deep enough to ensure that penstock inlet is completely submerged so that air is excluded from the power equipment.

TAIL RACE

The tail race is the flow of water out of the power house back into the stream.

RESERVE FLOW

Hydro-electric plants are designed to use only part of the total water flow under normal operating conditions, The reserve flow is the portion of the flow not normally used

INTAKE

The intake is a buffer between the water supply and the hydro-electric plant. It is constructed of earth, masonry, concrete, or riprap. It's shape is largely determined by the nature of the terrain.

FISH LADDER

The fish ladder allows salmon to migrate upstream to minimize the biological impact of the power plant.

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HYDRO ENERGY PRODUCTION EQUIPMENT

TURBINE

A hydraulic turbine is a rotating machine driven by water under pressure from a penstock or forebay. The energy in the flowing water is converted to mechanical energy by a revolving wheel fitted with blades buckets or vanes.

The flow is directed at the wheel by a nozzle or an injector allowing the flow to be adapted to the mechanical power required by the electrical equipment being driven.

CONTROLS

Generators must conform to characteristics of the electrical equipment they are powering. Control systems act to modify the water flow to the turbine to maintain the desired characteristics, or to dissipate excess energy.

SET UP GEARING

Electric generators are more efficient when they run at high speeds. If a turbine rotates at a low speed, "stem-up" gearing can be installed between the turbine and the power generator to increase the rotation speed.

GENERATOR

Generators convert the mechanical energy produced by the turbine into electrical energy. Different types of generators are used depending on the characteristics of the electrical grid the hydro-electric systems is connected to.

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