HYDROELECTRIC POWERPLANT

1. Forebay

2. Intake structure

3. Penstock

4. Surge chamber

5. Hydraulic turbines

6. Power house

7. Draft tube

8. Tailrace

The major components of a hydroelectric plant are as follows:

hydraulic turbines

Turbines that use water as the working fluid for the production of power are known as _______________.

1. Impulse turbines

2. Reaction turbines

CLASSIFICATION OF HYDRAULIC TURBINES:

This classification is based on the interaction of fluid with turbine blades.

head

In fluid mechanics, the term ______ indicates the energy in units of distance.

Gross head (ℎ𝑔)

Net head /effective head (h)

two types of heads as far as turbines are concerned:

Hydraulic efficiency (𝑒ℎ)

___________- is defined as the ratio of power developed by the turbine runner to power available at turbine inlet

Turbine efficiency (𝑒𝑡)

___________ − is defined as the ratio of turbine power output to the water power output

Mechanical efficiency (𝑒𝑚)

___________ - is the ratio of power available at the shaft to the power developed by the runner

Generator efficiency (𝑒𝑔𝑒𝑛)

_____________ - the ratio of the electrical power produced by the generator to mechanical power available at turbine–generator shaft

Overall efficiency (𝑒𝑜)

___________ - is the efficiency of whole turbine-generator system which can be obtained by dividing the power output of generator to the hydraulic power input to turbine

Volumetric efficiency (𝑒𝑣)

______________ - is defined as the ratio of actual discharge to the total discharge

Pelton turbine or Pelton wheel

The _________ or ________ is a tangential flow impulse turbine.

high head and low discharge, Pelton wheel

The water strikes the bucket along the tangent of the runner. Pelton turbine is a _________and _________ impulse turbine. Pelton turbine works on the principle of conversion of available hydraulic energy first into kinetic energy of the jet and then into mechanical energy of the rotating wheel or runner, also known as ___________.

Adverse water conditions, critical water conditions

______________ - water conditions that limit the production of hydroelectric power, either because of low water supply or reduced gross head or both. Sometimes called ___________

Appraisal study, reconnaissance study

____________ - a preliminary feasibility study made to determine whether a detailed feasibility study is warranted. Also called a _____________.

Armature, rotating or stationary

___________ - that part of an electric rotating machine that includes the main current carrying winding in which the electromotive force produced by magnetic flux rotation is induced; it may be ________or ________.

Availability

_________- the percentage of time a plant is available for power production.

Average availability

_____________ (also hydrologic availability) - the ratio of the average capacity of a hydroelectric plant in the peak demand months to its rated capacity. This ratio accounts for variations in streamflow and head.

Mechanical availability

____________ - the ratio of the number of days in total period minus days out of service due to maintenance and forced outages, to the number of days in the total period.

Average annual flow

___________- the rate at which water flows through a conduit or channel, determined by averaging daily measurements of this rate over the course of a year; normally expressed in cubic feet per second or cubic meters per second.

Average load

___________- the hypothetical constant load over a specified period of time that would produce the same energy as the actual load would produce for the same period.

Average water conditions

______________ - precipitation and runoff conditions which provide water for hydroelectric power development approximating the average amount and distribution available over a long time period, usually the period of record.

Axial hydraulic thrust

____________ - in single-stage and multistage pumps, the summation of unbalanced impeller forces acting in the axial direction.

Backwater

__________ - water level controlled by either a downstream reservoir, a channel restriction, or a stream confluence that affects the tailwater level of an upstream plant.

Black start

_________ - the startup of a powerplant without an external electrical supply.

Block loading

_____________ - a generating plant is said to be block loaded when its output is increased or decreased in definite steps without regard to following a particular load shape. A generating plant carries a block load when its output is maintained at a fixed level for an extended period of time

Bulb turbine

_________ - an axial flow turbine situated in a straight-through water passage.

Bulkhead gate

_________ - a gate installed at the entrance of a fluid passage and used to dewater the passage for inspection and maintenance. Almost always opened or closed under balanced pressure.

Equivalent thermal capacity

_______________ - the amount of thermal generating capacity that would carry the same amount of system peak load as could be carried by a given hydroelectric plant.

Hydraulic capacity

______________ - the maximum flow which a hydroelectric plant can utilize for energy.

Rated capacity

___________ - the electrical load for which a generator, turbine, transformer, transmission circuit, electrical apparatus, powerplant, or power system is rated.

Capacity/Plant factor

___________ - the ratio of the energy that a plant produces to the energy that would be produced if it were operated at full capacity throughout a given period, usually a year.

Cavitation

____________ - the formation of voids within a body of moving liquid (or around a body moving in liquid) when the local pressure is lower than the vapor pressure, and the particles of liquid fail to adhere to the boundaries of the passageway. These voids fill with vapor and then collapse, causing pitting of metal on turbine blades.

Cogeneration

__________- the use of waste heat to drive turbine generators for electricity generation. Also, the use of low-pressure exhaust steam from an electric generating plant to heat an industrial process or a space.

Cold reserve

_____________- reserve generating capacity available for service but not in operation.

Critical speed

____________ - the angular speed at which a rotating shaft becomes dynamically unstable with large lateral amplitudes, due to resonance with natural frequencies of lateral vibration of the shaft.

Critical streamflow

_____________ - the amount of streamflow available for hydroelectric power generation during the most adverse streamflow period.

Crossflow turbine

____________– a hydraulic machine that converts hydraulic energy to mechanical energy by allowing water to flow in one side, then out the other side of a cylindrical turbine runner.

Cycling

___________ - powerplant operation to meet the intermediate portion of the load (9 to 14 hours per day).

Dead storage

___________- the portion of a storage basin or reservoir that cannot be used for temporary water storage

Dependable capacity

____________ - the expected load-carrying ability of a hydropower plant under specified conditions

Deriaz turbine

____________ - a diagonal-flow turbine with a propeller runner whose blades are adjustable and the axis of the blades is at an angle with the axis of the shaft.

Design head

____________ - the head at which the runner of a turbine is designed to provide the highest efficiency. Measured in feet or meters.

Draft

__________ - the withdrawal of water from a reservoir.

Encroachment

___________ - the reduction in generating head at a hydroelectric project by a rise in tailwater elevation resulting from the backwater effects of a downstream reservoir.

Fuel displacement energy

___________ - electric energy generated at a hydroelectric plant as a substitute for energy which would otherwise have been generated by a thermal-electric plant.

Firm energy

___________- the energy generating ability of a hydropower plant in a specified time period and under adverse hydrologic conditions.

Forced vortex

______________- the rotation of a fluid, moving as a solid, about an axis where every particle of the fluid has the same angular velocity.

Free vortex

________ - rotation of a fluid where each particle moves in a circular path with a speed varying inversely as the distance from the center.

Governor

__________ - the device which measures and regulates turbine speed by controlling wicket gate angle to adjust water flow to the turbine.

Hydraulic loss

___________ - the loss in energy due to flow (friction and form loss)

Inflow

_________- the rate or volume of water that flows into a reservoir or forebay during a specified period.

Leaf

____________ - the elliptically shaped section of a wicket gate.

Low-head hydropower

________________- hydropower that operates with a head of 66 feet (20 m) or less.

Manifold

__________– a section of steel pipeline that divides flow from a single penstock into several smaller penstocks that feed multiple turbine generator units.

Regimen/ Dynamic Equilibrium

__________ - he major dimensions of the river channels remain relatively constant or stable over an extended period of time under current flow characteristics.

Sequential Streamflow Routing (SSR)

_____________ - the chronological routing of stream flows through a project or system of projects in order to define a project's firm yield, its energy or peaking power output, or its performance under specified operating criteria.

Sluice gate

__________- vertical-shaft slide gate often used for passing water through a dam. Manual or motor-operated floor stands are used to raise and lower ______.

Small hydropower

__________ - hydropower installations that are 15,000 kW {15 MW) or less in capacity.

Suspended load

_____________ - that part of the sediment load which is suspended in the water column and is transported farther above the streambed by turbulent eddies and moves downstream in an irregular path.

Tailrace, afterbay

___________ - a channel for conducting water away from a powerplant after it has passed through it. Sometimes called an __________.

Tailwater

____________- water surface downstream of the powerhouse.

Water hammer

_____________ - pressure changes in a pressure conduit or penstock that are caused by the flow variation with time.

Vortex

_________– a flow with closed streamlines