Indian power system becomes largest operating synchronous grid in the world

[shuntmaster]

the southern grid was connected with the national grid via HVDC link......does that mean they will be operating at different frequencies......

Yes, that's right.. The main reason why HVDC is used, is to interconnect asynchronous grids. There are many other side benefits too..

 

[45'22']

Yes, that's right.. The main reason why HVDC is used, is to interconnect asynchronous grids. There are many other side benefits too..

but there are some disadvantages as well......for ex......if the regional grids are connected through AC links.......and there is instability in a state grid......then the freq. drops below the limit say 47.5 Hz or rises above 52.5 Hz,then the other regional grids helps in compensating that effect.....but if they are connected by HVDC links..........then regional grid will trip......which can happen with our southern grid.......

 

[shuntmaster]

the southern grid was connected with the national grid via HVDC link......does that mean they will be operating at different frequencies......

Looks like I may be wrong on this.. Reading the original post of this thread again:

Till now, four regional grids namely northern, eastern, western and north-eastern regions (NEW grid) were connected synchronously and southern region (SR) was connected to this NEW grid through HVDC links. Synchronous interconnection of SR with NEW grid was envisaged through high capacity 765 kV Raichur - Sholapur lines, as an ultimate step towards establishment of an "All India Synchronous National Grid" facilitating bulk transfer of power across regional boundaries.

Its not clear whether the high capacity 765 kV Raichur - Sholapur lines are HVDC or normal AC. Its talks about "NEW grid through HVDC links" and also "All India Synchronous National Grid".

 

[45'22']

Its not clear whether the high capacity 765 kV Raichur - Sholapur lines are HVDC or normal AC. Its talks about "NEW grid through HVDC links" and also "All India Synchronous National Grid".

the link is a hvdc one

PGCIL commissions 765 kV Raichur-Sholapur transmission line

 

[CorporateAffairs]

What about andhra? No body is helping andhra

we have ourselves to blame for the mess

 

[shuntmaster]

but there are some disadvantages as well......for ex......if the regional grids are connected through AC links.......and there is instability in a state grid......then the freq. drops below the limit say 47.5 Hz or rises above 52.5 Hz,then the other regional grids helps in compensating that effect.....but if they are connected by HVDC links..........then regional grid will trip......which can happen with our southern grid.......

The HVDC link can regulate the power import & export between grids. The stability of a grids depends on the power generation capability and consumption demand. The HVDC link monitors this and accordingly regulates the power imported or exported from the grids and the response time can be in milliseconds.

 

[45'22']

The HVDC link can regulate the power import & export between grids. The stability of a grids depends on the power generation capability and consumption demand. The HVDC link monitors this and accordingly regulates the power imported or exported from the grids and the response time can be in milliseconds.

sometimes the sldc draws extra power than the requirements........due to which load on generator increases and freq. drops.........in that case if the freq drop exceeds the limit then the regional grid will trip .......but if the reginal grids are connected by AC links than the load will be shared and the decrease in freq. will not be much,and hence we can avoid the tripping of the regional grids.......isnt it correct

 

[shuntmaster]

sometimes the sldc draws extra power than the requirements........due to which load on generator increases and freq. drops.........in that case if the freq drop exceeds the limit then the regional grid will trip .......but if the reginal grids are connected by AC links than the load will be shared and the decrease in freq. will not be much,and hence we can avoid the tripping of the regional grids.......isnt it correct

Once the independent regional grids are interconnected by AC links, those grids no longer remain isolated regional grids, but become one big synchronous grid operating at same frequency. The stability dynamics of the smaller regional grids is applicable to the bigger grid too, only difference is the new grid becomes stronger i.e. has more generating capacity, fault levels go up etc.

 

[45'22']

Once the independent regional grids are interconnected by AC links, those grids no longer remain isolated regional grids, but become one big synchronous grid operating at same frequency. The stability dynamics of the smaller regional grids is applicable to the bigger grid too, only difference is the new grid becomes stronger i.e. has more generating capacity, fault levels go up etc.

but same doesnt happen with HVDC links which is a disadvantage though it saves the grid from outage and other problems

 

[shuntmaster]

but same doesnt happen with HVDC links which is a disadvantage though it saves the grid from outage and other problems

Thats not exactly right, HVDC allows the grids to remain in asynchronized condition i.e. allow the grids to operate at different frequencies, but allow power transfers between the grids which strenthens both the grids but doen't allow the problems of one grid to be passed on the other grid. If one grid collapses due to some reason, the HVDC link will isolate the other grid allowing it to continue to operate in islanded mode.