HVDC TRANSMISSION

PRESENTATION BY UTKARSH CHANDRA

KEY WORDS Introduction of Power grid Need of HVDC What is HVDC ? Evolution of HVDC. HVDC goes global. HVDC in INDIA. Price comparison of HVDC and HVAC. Circuit diagram of HVDC transmission Advantages of HVDC over HVAC Disadvantages of HVDC. Conclusion.

POWER GRID

• An electrical grid is an interconnected network for delivering electricity from suppliers to consumers.

ARE OF TWO TYPES

AC TRANSMISSION GRID

DC TRANSMISSION GRID

AC TRANSMISSION GRIDS

FOR SHORT DISTANCES• LOW COST

FOR LONG DISTANCES• TOO COSTLY

• VERY HIGH LOSSES

DC TRANSMISSION GRIDS

FOR SHORT DISTANCES• HIGH COST OF INSTALATION

FOR LONG DISTANCES•LESS LOSSES

• LOWER COST OF INSTALATION

NEED OF HVDC

• Generally, generation is done at long distances from the load.

• For efficient power transmission for long distances HVDC is used over HVAC.

WHAT IS HVDC ?• In a HVDC (High voltage D.C.) transmission system,

electricity is taken from an AC power network, converted to DC in a converter station and transmitted to the receiving point by a transmission line (overhead) or cable(underground). It is then converted back to AC in another converter station and injected

into the receiving AC network. HVDC enables the power flow

to be controlled rapidly and accurately, and improves the performance, efficiency and economy of the connected AC networks.

History of HVDC Firstly concept was developed by a swiss engineer ‘Rene

Thury’ during the end of 19th century.• In 1941 a 60MW 115km ‘Elbe-project’ was designed in Berlin(Germany),but couldn’t be completed.• However in 1954 first successful HVDC 20MW 96km commercial installation was done between the Gotland island and Sweden.

This transformer converted the first HVDC transmission in Gotland. This transformer converted

the first HVDC transmission in gotland

HVDC goes Global• Currently there are some more than 100 of

HVDC systems across the whole world ,out of which 6 are in India.

• Some of them are as follows: -Between Sweden & Denmark. -Between south & north islands of New Zealand. -Between Italy & Sardinia. -Between Los Angeles & Oregon. -Between north African deserts & central Europe. -Between UK & western Europe.

HVDC IN INDIA

In India presently 6 HVDC systems are in operation. India- Pioneer developer of HVDC since 1990 with the first HVDC set

up of 1500MW 814Km Rihand-Dadri line between U.P & Rajasthan. 2000MW 1440Km Talcher-Kolar link is biggest so far connecting four

states-orissa,andhra pradesh,tamilnadu and karnataka. In march 2000,Power-grid(largest power transmission utility of India)

awarded a new long distance HVDC transmission project to SIEMENS,Germany.

More greater plans are cooking to add 1lakh MW of power by 2012 in which HVDC will play vital role to transmit these powers to all corners of India.

Main data

Commissioning year: 1990

Power rating: 1 500 MW

No. of poles: 2

AC voltage: 400 kV (both ends)

DC voltage: ±500 kV

Length of overhead DC line:

814 km

Main reason for choosing HVDC:

Long distance, network stability

   

 

FACTS & FIGURES Data of Rihand-Dadri line Data of Talcher-

Kolar line Commissioned year 1990Power rating 1500MWNo. of poles 2AC voltage 400KV(both

ends)DC voltage 500KVLength of overhead DC line

814Km

Reason for choosing HVDC

Long distance, Network stability.

Commissioned year

14th Feb 2003

Power rating 2000MW

No. of poles 2

No. of towers 5651

Amount of steel 10,000 metric tone

Amount of cement 80,000 metric tone

Length of line 1400Km

Cost of project Rs.700 crore

PRICE COMPARISON BETWEEN HVDC AND HVAC

CIRCUIT DIAGRAMHVDC TRANSMISSION

ADVANTAGES Advantages of HVDC can be

classified as:

Advantages of dc transmission

Technical Advantages

EconomicAdvantages

Technical Advantages

• No charging current and no skin effect.• Controllability is easier .• Voltage regulation is better.• Lesser Corona Loss and Radio

interference• Reversibility.• Power can be transmitted between

unsynchronized grids.

Economic advantages•DC lines and cables are cheaper than AC.

•The towers of the dc lines are narrower, simpler and cheaper than ac.

•Line losses lesser than ac.

•Ground return is possible.

DISADVANTAGES

• End stations are too costly.

• Harmonics are generated.

• Reactive power transmission is not possible.

• DC voltage step up and step down is not possible.

CONCLUSIONSRecent studies states HVDC is more

reliable than HVAC.HVDC system can transmit power

between, UNSYNCHRONIZED GRIDS SO, cross-border transmission is possible.

HVDC is able to transmit large amounts of power over long distances with lower capital costs and with lower losses than AC.

ACKNOWLEDGEMENT• AMIT KUMAR YADAV (EE)• AMIT KUMAR (EE)• ARVIND PAL SINGH (EE)• DIBYAPRAKASH KUSHWAHA (EC)• ASHISH YADAV (EE)