Hydroelectric Power Plants

Water power was used to drive machinery long before Polzunov and James Watt harnessed steam to meet man’s needs for useful power. Modern hydroelectric power plants use water to activate the machines which generate electricity. They are built on rivers. Large-capacity hydroelectric power plants are commonly located at considerable distances from the consumers of electric power.

A hydraulic turbine and a generator are the main units of a hydroelectric power plant. Being the key machines converting the energy of flowing water into mechanical energy hydraulic turbines have the following principal parts: a runner composed of radial blades mounted on a rotating shaft and a steel casing which houses the runner.

The production process at hydroelectric plants is rather simple: the flowing water acts upon the runner blades and rotates the runner and the turbine shaft. The generator shaft is connected to the turbine runner shaft. Thus, the turbine drives the generator which produces electricity. The magnitude of the water head and the daily inflow of water fluctuates considerably according to the season and the difference in the water level influences the power capacity of a plant.

The locality of a hydroelectric plant depends on natural conditions. A hydroelectric power plant can be located either at a dam or at a considerable distance below. It depends on the necessity to use the head supply at the dam itself or the necessity to use a greater head. In the latter case, water is conducted through pipes or open channels to a point farther downstream where the natural conditions make a greater head possible.

The design of machines using water power greatly depends on the nature of the available water supply. In some cases great quantities of water can be taken from a large river with only a few feet head. In other cases, instead of a few feet we can have a head of several thousands of feet. In general, power may be developed from water by action of its pressure, its velocity or by the combination of both.

The production process is different at power plants of different constructions and of different kinds. In nuclear power plants, for example, it is not as simple as in hydroelectric plants.

· Transcribe the following words, practice reading them, give Russian equivalents:

Power, machinery, harness, hydraulic, turbine, convert, mount, runner, blade, shaft, influence, fluctuate, capacity, construction, nuclear, design, develop, pressure, velocity

· Are the following sentences true or false? Correct the false sentences.

1. Polzunov and James Watt were the first to use water for driving machinery.

2. Modern hydroelectric power plants are commonly located at considerable distances

from water sources.

3. A hydroelectric power plant consists of three principal parts.

4. The water level in rivers never changes.

5. The production process in hydroelectric plants is not as simple as in nuclear power

plants.

6. The design of water power machines depends on the water pressure and its velocity.

· Use the following paragraphs to answer the questions.

Paragraph 1

What is the prime mover of hydroelectric plants?

Paragraphs 2 and 3

Do generators convert the energy of flowing water into mechanical energy?

Paragraph 3

What influences the power capacity of a plant?

Paragraph 5

Does the magnitude of the water head depend on natural conditions?

Paragraph 6

Why are the machines using the water power designed in different ways?

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