Hydroelectric Power Plant Flashcards

Flashcards for key vocabulary related to hydroelectric power plants.

Desilting Tank

A tank used in hydroelectric power plants for desilting.

Headrace

A channel that carries water to the forebay in a hydroelectric power plant.

Forebay

A reservoir or holding area at the intake of a penstock.

Penstock

A closed conduit or pipe that delivers water to the turbine.

Powerhouse

The structure housing the turbines and generators in a hydroelectric power plant.

Tailrace

A channel that carries water away from the turbine after it has been used to generate power.

Hydraulic Turbines

Turbines that use water as the working fluid for power production.

Classification of Hydraulic Turbines

Turbines classified based on the interaction of fluid with turbine blades as either impulse or reaction turbines.

Pelton Turbine

Turbines in which the water strikes the buckets along the tangent of the runner.

Adverse water conditions

Water conditions that limit the production of hydroelectric power due to low water supply or reduced gross head.

Appraisal study

A preliminary study to determine if a detailed feasibility study is warranted.

Armature

The part of an electric rotating machine with the main current-carrying winding.

Availability

The percentage of time a plant is available for power production.

Average annual flow

The rate at which water flows through a conduit or channel, averaged over a year.

Average load

The hypothetical constant load over a specified period that would produce the same energy as the actual load.

Average water conditions

Precipitation and runoff conditions providing water for hydroelectric power development approximating the average amount and distribution over a long period.

Axial hydraulic thrust

The summation of unbalanced impeller forces acting in the axial direction in pumps.

Backwater

Water level controlled by a downstream reservoir, channel restriction, or stream confluence affecting the tailwater level of an upstream plant.

Black start

The startup of a powerplant without an external electrical supply.

Block loading

A generating plant whose output is increased or decreased in definite steps without regard to following a particular load shape.

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 to dewater the passage for inspection and maintenance.

Equivalent thermal capacity

The amount of thermal generating capacity that would carry the same amount of system peak load as 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 energy a plant produces to the energy it would produce if operated at full capacity throughout a given period.

Cavitation

The formation of voids within a moving liquid when the local pressure is lower than the vapor pressure, causing pitting of metal.

Cogeneration

The use of waste heat to drive turbine generators for electricity generation, or the use of low-pressure exhaust steam.

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.

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.

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 backwater effects.

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

Major dimensions of river channels remain relatively constant or stable over an extended period under current flow characteristics.

Sequential Streamflow Routing (SSR)

The chronological routing of stream flows through a project or system of projects to define a project's firm yield, output, or performance.

Sluice gate

Vertical-shaft slide gate often used for passing water through a dam.

Small hydropower

Hydropower installations that are 15,000 kW (15 MW) or less in capacity.

Suspended load

The part of the sediment load which is suspended in the water column and is transported downstream.

Tailrace

A channel for conducting water away from a powerplant after it has passed through it.

Tailwater

Water surface downstream of the powerhouse.

Water hammer

Pressure changes in a pressure conduit or penstock caused by flow variation with time.

Vortex

A flow with closed streamlines