Copy of `Wind Energy (the facts) - Glossary of wind turbines`

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Wind Energy (the facts) - Glossary of wind turbines
Category: Sciences > Glossary of wind turbines
Date & country: 21/12/2010, UK
Words: 126


Participatory planning
is a planning process open to higher levels of public engagement. Successful wind farm developments are linked to the nature of the planning and development process, and public support tends to increase when the process is open and participatory. Thus, collaborative approaches to decision-making in wind power implementation are suggested to be more...

Permanent magnet generator
(PMG) is a synchronous electrical generator design based on the use of permanent magnets on the rotor.

Photovoltaic generation
(PV) is the generation of electricity from sunlight or ambient light, using the photovoltaic effect.

Point of common coupling
(PCC) is the point on the public electricity network at which other customers are, or could be, connected. Not necessarily the same location as point of connection.

Point of connection
(POC) is the point at which the wind farm electrical system is connected to the public electricity system.

Pollutant
a substance that is present in concentrations that may harm organisms (humans, plants and animals) or exceed an environmental quality standard. The term is frequently used synonymously with contaminant.

Power curve
depicts the relationship between net electric output of a wind turbine and the wind speed measured at hub height on a 10-minute average basis.

Primary control


Primary control power
is the power output of a generation set due to primary control.

Primary control range
is the range of adjustment of primary control power, within which primary controllers can provide automatic control, in both directions, in response to a frequency deviation. The concept of the primary control range applies to each generator, each control area/block and the entire synchronous area.

Primary control reserve
the (positive/negative) part of the primary control range measured from the working point prior to the disturbance up to the maximum primary control power (taking account of a limiter). The concept of the primary control reserve applies to each generator, each control area/block and the entire synchronous area.

Primary controller
decentralised/locally installed control equipment for a generation set to control the valves of the turbine, based on the speed of the generator (see primary control). The insensitivity of the primary controller is defined by the limit frequencies between which the controller does not respond. This concept applies to the complete primary controll...

Productivity
is used here as employees per output unit in fixed prices. The 2 per cent increase in productivity used as a basic assumption implies that 2 per cent less people are needed to produce the same output every year. If additional cost reductions of turbines are assumed, this must partly be attributed to additional productivity increases further reducin...

Progress ratio
is related to the learning rate (see learning rate) – if the learning rate is 15 per cent, then the progress ratio is 85 per cent.

PX
is a power exchange scheduling coordinator and is independent of system operators and all other market participants.

Rated wind speed
is the lowest steady wind speed at which a wind turbine can produce its rated output power.

Reactive power
is an imaginary component of the apparent power. It is usually expressed in kilo-vars (kVAr) or mega-vars (MVAr). Reactive power is the portion of electricity that establishes and sustains the electric and magnetic fields of alternating-current equipment.

Reactive power
must be supplied to most types of magnetic equipment, such as motors and transformers, and causes reactive losses on transmission facilities. Reactive power is provided by generators, synchronous condensers or electrostatic equipment such as capacitors and directly influences the electric system voltage. The reactive power is the imaginary part of ...

Reinvestments
are the costs of replacing a larger and more costly part of a turbine.

Reliability
describes the degree of performance of the elements of the bulk electric system that results in electricity being delivered to customers within accepted standards and in the amount desired. Reliability at the transmission level may be measured by the frequency, duration and magnitude (or the probability) of adverse effects on the electric supply/tr...

Reynolds number
a dimensionless number describing the aerodynamic state of an operating aerofoil. The number is used along with the angle of attack to describe the limits of a particular aerofoil`s lift-to-drag ratio and the conditions at which stall occurs. Small wind turbine aerofoils typically operate in a low Reynolds number range, from 0.150 to 0.5 mi...

Rural electrification
provides a regular supply of electricity to rural residents. It implies the extension of power lines to rural areas, or the use of stand-alone or isolated power systems.

Savonius rotor
(S-rotor) a simple drag device producing high starting torque developed by the Finnish inventor Sigurd J. Savonius.

SCADA
see supervisory control and data acquisition system.

Secondary control
is a centralised automatic function to regulate the generation in a control area, based on secondary control reserves in order to maintain its interchange power flow at the control programme with all other control areas (and to correct the loss of capacity in a control area affected by a loss of production) and, at the same time, in the case of a m...

Tip speed
speed (in m/s) of the blade tip through the air.