HVDC systems accounted for nearly 30 per cent of the total interregional electricity exchange in FY21, according to a special study by T&D India based on official statistics.
In FY21, a total of 214,766 MU (million units or million kwh) of electricity exchange took place between the five regional grids of India – NR (northern), WR (western), ER (eastern) SR (southern) and NER (northeastern). [See related story.]
HVDC lines, including HVDC back-to-back systems, saw a total transfer of 63,434 MU, implying a share of 29.5 per cent in the total interregional electricity exchange in FY21.
The ±500kV Talcher-Kolar line was the busiest HVDC link in FY21, transferring 14,401 MU of electricity—all of it from ER to SR. Also known as the East-South Interconnector, the Talcher-Kolar line, owned by Power Grid Corporation of India Ltd (PGCIL), has a transfer capacity of 2,500 mw. Commissioned in 2003, the bipolar line runs 1,450 km from Odisha to Karnataka.
The ±800kV Champa-Kurukshetra line transferred 13,775 MU – entirely from WR to NR. This line, also owned by PGCIL, is a multi-terminal system and is regarded as amongst the longest HVDC system in the world. It runs around 1,300 km and is equipped with four poles—each with a transfer capacity of 1,500 mw.
While most of the existing interregional HVDC systems are owned by PGCIL, the ±500kV Mundra-Mohindergarh HVDC line, owned by private entity Adani Transmission Ltd, is a significant exception. This line ferried 12,026 MU in FY21, accounting for nearly one-fifth of the total quantum of interregional HVDC-based transfers in FY21. Running from Gujarat to Haryana (with over 3,800 ckm of line length), this line helps evacuate electricity from Adani Group’s Mundra and Tiroda thermal power plants, located in Gujarat and Maharashtra, respectively.
Raigarh-Pugalur link
The ±800kV Raigarh-Pugalur HVDC system of PGCIL is the latest addition to India’s HVDC lines. This line became commercially operational in September 2020 with the commissioning of the first pole. The second pole was subsequently commissioned in March 2021. In FY21 (with seven months of operation), the Raigarh-Pugalur line transferred 3,984 MU from WR to SR. There was also a small reverse transfer of some 136 MU from SR to WR.
Power transfer to SR is expected to get a boost, thanks to the Raigarh-Pugalur HVDC line that has a rated capacity of 6,000 mw. This 1,750-km line runs from Chhattisgarh to Tamil Nadu. It may be mentioned that this line has a ±320kV VSC-based HVDC line from Pugalur to Trichur in Kerala. This component was fully commissioned earlier this month, and is expected to fulfill energy deficit in Kerala.
Beneficiaries
NR and SR are high power consumption centres and much of India’s interregional power transfer is destined to these two regions. Even the basic purpose of HVDC systems in India was to enable efficient power transmission to these two regions, from power generation centres located in ER, WR and NER. In FY21, over 52 per cent of the total electricity exchange through HVDC systems was destined to NR. A little under 43 per cent was transferred to SR.
(Note: This study is based on official statistics released by Power System Operation Corporation Ltd. Featured photograph shows the converter hall associated with PGCIL’s Champa-Kurukshetra HVDC system.)
