PHEP12 Surge Chambers

Question 1

Penstock velocities may range from:

Answer 1

6 to 20 ft/sec.

Question 2

In most hydroelectric developments the head and water flow will:

Answer 2

Fluctuate

Question 3

Wood-stave pipe would probably not be used for:

Answer 3

Heads above 500 feet.

Question 4

Steel pipe is used more extensively than any other type of pipe for penstock construction because:

Answer 4

Of the degree of flexibility it offers in satisfying design criteria in all of the following:

It can be riveted
It can be welded
It is better able to withstand changes in static dynamic pressures

Question 5

Which of the below conditions would probably not cause the water level in the riser of a differential surge tank to fall?

Answer 5

A load rejection.

Question 6

Positive water-hammer pressure caused by a sudden decrease in the demand for water can be eliminated by:

Answer 6

Any of the bellow:

Relief valve
Pressure regulator
Surge tank

Question 7

A partially clogged trash rack will:

Answer 7

Cause a decrease in the effective head.

Question 8

The best canal cross-section from a hydraulic point of view is defined as:

Answer 8

The one that has a minimum wetted perimeter.

Question 9

The least efficient type of high-line conduit is that type which:

Answer 9

Has the greatest effect on the available head.

Question 10

One of the major advantages of using a pressure tunnel in a power conduit system is that:

Answer 10

It permits full use if the available head.

Question 11

An open conduit system implies:

Answer 11

The presence of a free surface.

Question 12

Pumped storage type of hydroelectric developments implies a capability for all the following:

Answer 12

Improving load factors on inter-connected power system stam plants

Providing a wider range of power system reserve capacity

Improve peak load operation

Question 13

Intake design has a large effect on:

Answer 13

Velocity

Volume

Head

Question 14

The head obtained by subtracting the head loss from conveyance of the water to the turbine by conduit, through the turbine and back to the river, subtracted from the gross head is called:

Answer 14

Effective head.

Question 15

What type of turbine has variable vane design and can be used for both pumping and generating:

Answer 15

Deriaz

Question 16

Small ice needles which form at the bottom of fairly quiet, shallow bodies of open water are called:

Answer 16

Anchor ice

Question 17

A protective relay which responds to a difference in values of current at two different points in a circuit is known as a:

Answer 17

Differential relay.

Question 18

A surge tank is normally designed to accommodate how much of the water load rejected by the turbines?

Answer 18

All of the load rejected.

Question 19

The minimum velocity of water in a power canal to prevent the deposit of silt is:

Answer 19

2 to 3 feet per second.

Question 20

With a higher velocity, the cross-section of a conduit or conductor can be _____________ for a given quantity of flow.

Answer 20

Smaller.

Question 21

An alternative to lining a canal for protection against erosion is to:

Answer 21

Increase the cross-section of the canal.

Question 22

Open conduits constructed in natural ground are called:

Answer 22

Canals.

Question 23

A riveted pipe produces a lower hydraulic loss than a fabricated welded pipe.

Answer 23

False

Question 24

The conduit between the turbines and the surge tank is called the:

Answer 24

Penstock

Question 25

What is meant by the term “wetted perimeter”?

Answer 25

Surface area that is in contact with the water.

Question 26

A base-load plant is a plant without pondage and where the full plant discharge is the same as the flow of the river.

Answer 26

False.

Question 27

The two types of surge tanks are:

Answer 27

Simple

Differential

Question 28

What are used to prevent excessive rise of the water at any point in a hydraulic development?

Answer 28

Spillways.

Question 29

To prevent negative pressure in a penstock where pipe is being used what is installed in the pipeline?

Answer 29

Air vents.

Question 30

The best hydraulic rectangular cross-section occurs when:

Answer 30

Y = B / 2

Y = water depth
B = bottom width

Question 31

Negative water-hammer pressure is created by:

Answer 31

A sudden increase in the demand for water.