SEMINAR BY MOHD ABDUL SOHAIL.ROLL.NO.160713734005.from final year

Introduction .Introduction .HVDC link’s.HVDC link’s.Basic principle’s.Basic principle’s.Components of HVDC. Components of HVDC. Cost of HVDC over HVAC.Cost of HVDC over HVAC.Advantages of HVDC over HVACAdvantages of HVDC over HVACDisadvantages of HVDC.Disadvantages of HVDC.Object’s of control.Object’s of control.Conclusion.Conclusion.

KEY WORDSKEY WORDS

HVDC stands for High Voltage Direct Current HVDC stands for High Voltage Direct Current and is today a well-proven technology and is today a well-proven technology employed for power transmission all over the employed for power transmission all over the world. world.

HVDC technology is used to transmit HVDC technology is used to transmit electricity over long distances by overhead electricity over long distances by overhead transmission lines or submarine cables. transmission lines or submarine cables. 

It is also used to interconnect separate power It is also used to interconnect separate power systems, where traditional alternating current systems, where traditional alternating current (AC) connections can not be used.(AC) connections can not be used.

INTRODUCTIONINTRODUCTION

HVDC links can be broadly HVDC links can be broadly classified into:classified into:

Monopolar links :used Monopolar links :used oneone conducter. conducter.

Bipolar links:used Bipolar links:used twotwo conducters. conducters.

Homopolar links:Homopolar links:twotwo are more are more conductersconducters

BASIC PRINCIPLES OF

HVDC TRANSMISSIONHVDC systems and FACTS controllers based on HVDC systems and FACTS controllers based on line-commutated converter technology (LCC)line-commutated converter technology (LCC)

Converters:Converters:

smoothing reactors smoothing reactors ElectrodesElectrodes Harmonic filtersHarmonic filtersReactive power suppliesReactive power suppliesDC linesDC lines

AC circuit breakers:AC circuit breakers:

Components of HVDCComponents of HVDC Transmission Systems:Transmission Systems:

COST OF HVDC OVER HVAC

– CONVENTIONALLY POWER TRANSMISSION IS EFFECTED THROUGH HVAC SYSTEMS ALL OVER THE WORLD.

– HVAC TRANSMISSION IS HAVING SEVER LIMITATIONS LIKE LINE LENGTH , UNCONTROLLED POWER FLOW, OVER/LOW VOLTAGES DURING LIGHTLY / OVER LOADED CONDITIONS,STABILITY PROBLEMS,FAULT ISOLATION ETC

– CONSIDERING THE DISADVANTAGES OF HVAC SYSTEM AND THE ADVANTAGES OF HVDC TRANSMISSION , POWERGRID HAS CHOOSEN HVDC TRANSMISSION FOR TRANSFERRING 2000 MW FROM ER TO SR

COMPARISION OF HVAC & HVDC SYSTEMS

Direct current is put to use in common life for driving our portable devices, UPSs, battery systems and vastly in railway locomotives.

USE OF DC

DC AS A MEANS OF TRANSMISSIONDC AS A MEANS OF TRANSMISSION

This has been possible with beginning of

High power/ high current capability thyristor.

&

Fast acting computerized controls

ADVANTAGESTechnical advantages:No requirement of reactive powerPractical absence of transmission line length

limitationsNo system stability problemsInterconnection of asynchronously operated power

systemsNo production of charging current

DisadvantagesDisadvantagesUse of converters ,filters etc increases the Use of converters ,filters etc increases the overall costoverall costDC circuit breakers are more expensiveDC circuit breakers are more expensiveHVDC converters have low overloading HVDC converters have low overloading capacitycapacityMore maintenance is required for insulatorsMore maintenance is required for insulatorsVoltage transformation is possible only on AC Voltage transformation is possible only on AC sideside

OObjectives of Controlbjectives of Control Efficient and stable operation.Efficient and stable operation.

Maximum flexibility of power control without Maximum flexibility of power control without compromising the safety of equipment.compromising the safety of equipment.

Principle of operation of various control systems.Principle of operation of various control systems.

Implementation and their performance during Implementation and their performance during normal and abnormal system conditions.normal and abnormal system conditions.

ConclusionConclusionHVDC is very important issue in transmission energy. HVDC is very important issue in transmission energy.

Problem of cascade blackout, can be reduced by Problem of cascade blackout, can be reduced by application of HVDC. application of HVDC.

Very large investments in e.g in China and India shows Very large investments in e.g in China and India shows that high-voltage direct current will very important in that high-voltage direct current will very important in the future, especially in big, new-industries countries.the future, especially in big, new-industries countries.

Recent studies indicate that HVDC systems are very Recent studies indicate that HVDC systems are very reliable.reliable.

The data collected from 31 utilities says that forced The data collected from 31 utilities says that forced unavailability of energy due to the converter station is unavailability of energy due to the converter station is 1.62%.1.62%.

If DC is required to be used for transmission

&

since our primary source of power is A.C,

The following are three basic steps:-

1. Convert AC into DC (rectifier)

2. Transmit DC

3. Convert DC into AC ( inverter)

Any