Advantages Of Hvdc Over Ac Transmission 5k4p4o

ADVANTAGES OF HVDC OVER AC TRANSMISSION

The main reason behind the HVDC transmission:

 Under sea cables (e.g. 250 km Baltic Cable between Sweden and ).  Endpoint-to-endpoint

long-haul

bulk power transmission without intermediate 'taps', for example, in remote areas. existing power grid in situations additional

wires

are

difficult or expensive to install.  Allowing between

power

transmission

unsynchronised

AC

distribution systems.  Reducing the profile of wiring and pylons for a given power transmission capacity. plant to the distribution grid. increasing

prospective

circuit current.

terminal stations are more expensive in the HVDC case due to the fact that they must perform the conversion from AC to DC and vice versa. But above a certain the

so-called

"break-even

distance", the HVDC alternative will always give the lowest cost. The

break-even-distance

is

much

smaller for submarine cables (typically about 50 km) than for an overhead line transmission. The distance depends on several factors (both for lines and cables) and an analysis must be made for

each

individual

case.

distance concept should not be overstressed, since several other factors,

 Stabilising a predominantly AC maximum

transmission capacity. However, the

The importance of the break-even-

 Connection of remote generating

power-grid,without

costs less than an AC line for the same

distance,

 Increasing the capacity of an where

A HVDC transmission line

short

such as controllability, are important in the selection between AC or HVDC.

(Typical

investment

Drawback

of

costs

for

the

an

overhead

HVDC

line

transmission

with

AC

and

HVDC).

system requires good communication between all the terminals.

Transmission system: The required static invertors are expensive and cannot be overloaded

APPLICATION

OF

HVDC

TRANSMISSION IN INDIA: Rihand

-

Delhi

and

very much. At smaller transmission



distances the losses in the static inverters

Chandrapur - Padghe were the

may be bigger than in an AC powerline,

first

and the cost of the inverters may not be

projects in India. The 1500 MW

offset by reductions in line construction

Rihand - Delhi transmission was

cost. In contrast to AC systems, realizing

put into service in 1990. It

multiterminal systems is complex, as is

transmits

expanding

Rihand

existing

schemes

to

long

distance

power -

HVDC

from

Singrauli

the

thermal

Controlling

power complex with a combined

power flow in a multiterminal DC

power generation of several

multiterminal

systems.

thousand MW, over a distance

of 814 km to Dadri station, close

(DOE),

to the capital of India.

sponsored a project under the



The

1500

Chandrapur

MW

-

transmission

Padghe

was

put

into

Govt.

national

of

HVDC

programme

on

India, R

&D

"Research,

Development and Training in

service in 1998. It transmits

HVDC

Transmission

power from the Chandrapur in

Technology" at IIT Kanpur.

the eastern part of Maharashtra over a distance of 736 km to the Mumbai area. 

In

CONCLUSIONS:

1983-84,

when

The Project has provided the

decision was being taken to

necessary

introduce

India,

infrastructure facilities to carry out

Government of India ed

research and development activities

a

concerning

100

HVDC kV,

in 100

MW



analysis,

to

build

operation

an

and

experimental line HVDC project

control of integrated DC power system.

- called National HVDC project

In addition to manpower training the

- with the sole objective of

facilities have been extensively used for

developing

the following purposes:

indigenous

technology,

entrusted

its

BHEL.

This

execution

to

monopole

project

involved

conversion of one circuit of existing double circuit 220 kV AC lines between Lower Sileru (Andhra Pradesh) and Barsoor (Madhya Pradesh) to HVDC transmission on the same tower. 

Consequently, in 1986,

the Department of Electronics

 To develop software for simulation and analysis of HVDC systems.  To develop and test new concepts in microprocessor based control and protection of HVDC converter and Static Var System.

 To carry out research in

ac

system. b) Application of expert

a) Operation & Control of HVDC links connected to weak

REFERENCE:  S.RAO – “EHV –AC, HVDC TRANSMISSION AND DISTRIBUTION ENGINEERING”.  C.L.WADHWA – “ELECTRICAL POWER SYSTEMS”.

system

approach

converter control

for

HVDC