1

GRID

Power CompensationPOWER COMPENSATION

Customer Benefits• Money Savings• More power• Less CO2 • A range of products based

on field-proven experience

Why do we need Power Compensation ?

Who

Power consumers, network operators, power •supplier, power industry, hospitals, offices, public buildings, factories

Solution

The power factor of a facility can be improved •by installing capacitor banks

Impact of reactive power

Transmission equipment has to be sized for the •apparent power, yet only active power is usefulIncreased losses in the network • You pay for apparent power but use active •power (higher electricity bill) Penalty fees to customers with a low power •factor (example < 0.95)

Power factor correction

Connected equipment (transformers, motors, air-conditioning, refrigerators, etc.) cause a phase angle between current and voltage. When the current is phase-shifted, it takes more current to deliver the same amount of active power.

An Alstom Grid company

« Power Quality saves money »

Dephasing between current and voltage decreases the active power (only the active power is converted into useful mechanical power).

Power factor = Active power / Apparent power

Voltage and currentshould be like this... but are like that.

1,51

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(maximum active power)

Voltage Current

(deteriorated active power)

Voltage Current

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Apparent Power

2

POWER COMPENSATION

Why do we need Power Compensation?

Impact of harmonics on transmission / distribution equipment

Additional losses (paid for by the end user) •Heating in power cables •Audible noise (transformers) •

Impact of harmonics on equipment connected

Decreased machine efficiency and lifetime •Costly process shutdowns • Disturbed electronic equipment •(computers, telephones)

Harmonic filtering

Variable speed drives (process industries, lifts, air conditioning pumps, etc.),

uninterruptible power supplies for computers, electronic equipment, etc. distort the current (introduce harmonics).

Who

Power consumers, network operators, power •supplier, power industry

Solution

Harmonics can be filtered through a •combination of reactors and capacitors (passive filtering) or by injecting the exact opposite of the harmonics detected (active filter) into the network

Currentshould be like this... but is like that.

Time (ms)

Time (ms) Current oscillogram before filtration

Curr

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Curr

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3

POWER COMPENSATION

Series Compensation

Long overhead lines cause the voltage to drop along the line. More current is needed to deliver the same power.

Main Advantages

• Today, Alstom Grid is the only international company to provide both air-core reactors and capacitors, the key elements for medium and high voltage reactive power compensation solutions

• We analyze the electrical installation of our customers (industries or utilities) to propose and supply the most suitable compensation solution

• Complete solutions have been designed and manufactured by our Tampere (Finland) unit for more than 50 years (Nokian Capacitors factory acquired by Alstom Grid in January 2008). We currently carry out this activity also in Brazil, Mexico and China

Who

Transmission utilities •

Solution

Voltage could be increased with the help of •capacitor banks connected in series

Impact

Decreased useful power • Aditional losses (network power losses are •proportional to the square of the current) Reduced transmission capacity of the •overhead line

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Voltage

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POWER COMPENSATION

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Alstom Grid Worldwide Contact Centre www.grid.alstom.com/contactcentre Tel: +44 (0) 1785 250 070 www.grid.alstom.com

Benefits of power factor correction

German example

By decreasing the electrical losses in the transmission and distribution networks, and hence reducing the emissions of CO2, this technology is making an active contribution to reducing global warming.

Benefits of power factor correction

• Power factor correction reduced network losses in Germany in 1999 by 9 billion kWh (5.1 million ton of CO2)

• With the maximum possible use of power factor correction, there is the potential for a further reduction in network losses of 4.3 billion kWh

• An additional improvement can be obtained by harmonic filtering, avoiding harmonic currents flowing in the network

Source: German electrical and electronic manufacturers’ association – September 2003

« Power Quality saves money »

27,4billionkWh

27,4billionkWh

36,4billionkWh

9 billion kWh

4,3 billion kWh

Fullcorrection

Partialcorrection

(status quo)

Nocorrection

23,1billionkWh

Current-dependent network losses (1999 values)

Power Compensation brings

Economic benefits

Saving the costs of reactive power • • Additional savings through reduced active power lossesReduction in investment cost •

Return on investment is generally below 18 months.

By saving millions of tons of CO2, power compensation makes

an active contribution to protecting the environment

Environmental benefits

• Reduced CO2 emissions Customers see environmental benefits through energy savings and more efficient power systems