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Electrical Energy Transmission byHigh-voltage Direct Current (HVDC)

and Prospects for an Electrical Market

Electrical Energy Transmission byHigh-voltage Direct Current (HVDC)

and Prospects for an Electrical Market

Mohamed Lakhdar HABIB and Rime BOUAROUDJMohamed Lakhdar HABIB and Rime BOUAROUDJ

18th APUA CongressLuanda, Angola, on 02-06 June 2014

General Theme « The energy mix in Africa : challenges and prospects »

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Introduction

Characteristics of Algerian SPTE

HVDC vs AC

Configurations of HVDC systems

Potential solar site in Algeria and Algerian transmission network

Outline

Applications and results

Maghreb interconnections

Regional integration of a power market

Maghreb - Europe Interconnections

Electrical Energy Transmission by HVDC Networks and Prospects for an Electrical Market

Conclusions and Prospects

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Introduction

Why interconnections?-Security of provision and functioning-Economical use of resources and reduction in investment costs

Types of interconnections:- Synchronous via alternative current (AC) systems - Asynchronous via direct current (HVDC or DC) systems

Areas where DC is used:

- Long distance transmission of the production of power plants to consumption centers- Integration of renewable energy generation systems into electrical systems-Interconnections of asynchronous networks -Submarine/ subterranean links for distances > 50 km.

Why interconnections?-Security of provision and functioning-Economical use of resources and reduction in investment costs

Types of interconnections:- Synchronous via alternative current (AC) systems - Asynchronous via direct current (HVDC or DC) systems

Areas where DC is used:

- Long distance transmission of the production of power plants to consumption centers- Integration of renewable energy generation systems into electrical systems-Interconnections of asynchronous networks -Submarine/ subterranean links for distances > 50 km.

Electrical Energy Transmission by HVDC Networks and Prospects for an Electrical Market

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HVDC vs AC

HVDC

No reactive effects, (unit power factor.).

Easy interconnection of networks, suffice it to have the same voltage everywhere.

No « skin » effect, the cables and lines are simple and inexpensive.

AC

Possibility of using transformers to increase and decrease voltage.

Facilitates power shut-down by the natural passage by zero, twice per period (available circuit-breaker).

Transmission and consumption of direct production by the alternators.

VSImpossibility of voltage generation or increase in the field of very high voltage, hence the significant losses on lines.

Difficulty of switching off direct currents, hence the need for better performing and expensive power shut-off devices.

Very expensive terminations.

Implies inductive and capacitive effects (power factor <1 mainly).

The interconnection of several networks requires the identity of the voltage, frequency and the phase.

Implies a «skin» effect, hence the necessity of adapted and more expensive cables and lines.

Advantages

drawbacks

Each drawback of the AC system is met with an advantage of the HVDC system and vice versaEach drawback of the AC system is met with an advantage of the HVDC system and vice versa

Electrical Energy Transmission by HVDC Networks and Prospects for an Electrical Market

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For the same level of redundancy, two (2) HVDC conductors equivalent to 02 three-phase lines.

The cost per « km » increases according to distance, up to a certain distance (600 Kms) and the alternative current remains more economical. Beyond this, transmission via direct current becomes necessary.

HVDC vs AC

Electrical Energy Transmission by HVDC Networks and Prospects for an Electrical Market

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Configurations of HVDC systems

Unipolar Bipolar

Multi-terminals

Back to Back

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Electrical Energy Transmission by HVDC Networks and Prospects for an Electrical Market

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Potential solar site in Algeria and Algerian transmission network

Electrical Energy Transmission by HVDC Networks and Prospects for an Electrical Market

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Characteristics of the Algerian SPTE

Demand for electricity:10 464 MW in 2013 at 40 600 MW by 2030, (8%)

Generation system:12 000 MW in 2013 at 50 000 MW by 2030,dont 12 000 MW in renewable energy.

Power network transmission :02 levels of transmission voltage : 220 kV and 400 kV

In 2013 : 4 500 km (11 000 km - 220 kV and 3 500 km - 400kV) 105 stations (11 in 400/220 kV and 89 in 220/60 kV)

By 2025: 31 400 km (20 000 km - 220 kV and 11 000 km - 400 kV) 245 stations (45 in 400/220 kV and 200 in 220/60 kV)

Demand for electricity:10 464 MW in 2013 at 40 600 MW by 2030, (8%)

Generation system:12 000 MW in 2013 at 50 000 MW by 2030,dont 12 000 MW in renewable energy.

Power network transmission :02 levels of transmission voltage : 220 kV and 400 kV

In 2013 : 4 500 km (11 000 km - 220 kV and 3 500 km - 400kV) 105 stations (11 in 400/220 kV and 89 in 220/60 kV)

By 2025: 31 400 km (20 000 km - 220 kV and 11 000 km - 400 kV) 245 stations (45 in 400/220 kV and 200 in 220/60 kV)

Electrical Energy Transmission by HVDC Networks and Prospects for an Electrical Market

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Applications and results

Electrical Energy Transmission by HVDC Networks and Prospects for an Electrical Market

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Maghreb interconnections

Electrical Energy Transmission by HVDC Networks and Prospects for an Electrical Market

Caption

400 kV 400 kV in project 220 kV

150 kV 90 kV

2009-2010

1988-199219521984

19801954

AlgeriaMorroco

Tunisia Libya

Technical and economic advantages of this interconnection :

-instant power backup at each network in harsh situations-Reduction in generation cost by pooling the spinning reserve - Economies on investment

But: limited energy exchange

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Regional integration of a power market

Electrical Energy Transmission by HVDC Networks and Prospects for an Electrical Market

In Maghreb, several enabling factors

 •Functioning in interconnected networks for long years.

•Trade with neighboring countries for more than 10 years.

•ONEE and Sonelgaz are external operators on the Iberian electricity market (OMIE).

•Availability of primary power resources, namely renweable energy.

•Sustained growth of demand throughout the countries in the region.

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Maghreb – Europe Interconnections

Electrical Energy Transmission by HVDC Networks and Prospects for an Electrical Market

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Conclusions and Prospects

Electrical Energy Transmission by HVDC Networks and Prospects for an Electrical Market

• Existence of a basic infrastructure to launch a Maghreb power market

• Massive development of renewable energies in Maghreb, an additional factor towards the establishment of a Euro-Maghreb power market.

• Construction of important links possibly in direct current to transmit solar energy from the South to the North of Algeria

• Construction of submarine links between Maghreb countries and Europe in view of a Euro – Maghreb power market

• Pursue efforts to remove institutional and legislative barriers relating to the implementation of a power market.

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Electrical Energy Transmission by HVDC Networks and Prospects for an Electrical Market