CHAPTER-2
OVERVIEW OF REGIONAL GRIDS
2.1 Power system in the country is divided into five regional grids namely Northern, Western, Southern, Eastern and North Eastern grids. Except for Southern grid, remaining four regional grid operate in synchronism. Southern grid is connected to Eastern and Western grids through asynchronous links.
2.2 Northern Regional Grid
2.2.1 Northern Region is the largest in geographical area amongst the five regions in the country covering approximately 31% of the area and having largest number of constituents. It has largest sized hydro unit (250 MW at Tehri/ Nathpa Jhakri) in the country. Northern Grid has an installed generating capacity of about 56,058 MW as on 30.06.2012 comprising 34608 MW of thermal and 19830 MW of Hydro generation The Thermal-Hydro (including renewable) mix is of the order of 64:36. The installed capacity of nuclear stations is 1620 MW.
2.2.2 Major generating stations including Super Thermal Power Stations of NTPC at Rihand and Singrauli are located in the eastern part of the NR grid. Due to such concentration of generation in the eastern part of the grid and major load centers in the central and western part of the grid there is bulk power transmission from eastern to western part over long distances. To handle this bulk transmission of power, a point to point high voltage DC line viz. HVDC Rihand-Dadri bipole with capacity of 1500 MW exists and operates in parallel with 400 kV AC transmission network besides under lying 220 kV network.
2.2.3 During the month of July, 2012 the Peak demand of Northern Region was 41,659 MW against the Demand Met of 38,111 MW indicating a shortage of 3,548 MW (8.5%). The energy requirement of Northern Region was 29,580 MU against availability of 26,250 MU indicating shortage of 3,330 MU (11.3%.).
2.3 WESTERN REGIONAL GRID
The Western Grid has an installed capacity of 66757 MW (as on 30-06-2012) consisting of 49402 MW thermal, 7448 MW hydro, 1,840 MW nuclear and 7909.95 MW from renewable energy sources.
2.4 EASTERN REGIONAL GRID
The Eastern Grid has an installed capacity of 26838 MW (as on 30-06-2012) consisting of 22545 MW thermal, 3882 MW hydro and 411 MW from renewable energy sources. The Eastern Regional grid operates in synchronism with Western, Northern and North-Eastern Regional grids.
2.5 NORTH-EASTERN REGIONAL GRID
2.5.1The North-Eastern Grid has an installed capacity of 2454.94 MW as on 31-03-2012 consisting of 1026.94 MW thermal, 1200 MW hydro and 228.00 MW from renewable energy sources. The North-Eastern Grid operated in synchronism with Northern Grid, Eastern Grid and Western Grid. North Eastern Regional Grid is connected directly only to the Eastern Regional Grid and any export of power to the other Regions has to be wheeled through the Eastern Regional Grid.
2.5.2The power transfer from North-Eastern Region to Eastern Region is taking place over Bongaigaon – Malda 400 kV D/C lines and Birpara – Salakati 220 kV D/C lines.
2.6 Inter-regional interconnections
The interconnections between various regional grids is depicted in Exhibit 2.1
