The Raigarh-Pugalur-Trichur high-voltage direct current (HVDC) transmission project will facilitate the transmission of up to 6GW of electricity between the northern and southern regions of India.
It is expected to be one of the world’s biggest multi-terminal HVDC systems to come online. It is also the first HVDC system in India to incorporate the voltage source converter (VSC) technology.
The project is being executed by India’s state-owned Power Grid Corporation of India (PGCIL) with an estimated investment of £2.1bn (Rs200bn).
It comprises four 800kV HVDC transmission lines from Raigarh (Chhattisgarh) to Pugalur (Tamil Nadu) over a route distance of approximately 1,765km, and a 250km-long 320kV HVDC line from Pugalur to Thrichur (Kerala).
The transmission capacity of each of the four poles of the two-way Raigarh-Pugalur line will be 1.5GW, while the Pugalur-Thrissur HVDC system will be capable of transmitting 2GW.
The first pole of the Raigarh-Pugalur transmission line was commissioned in September 2020. The remaining three poles are expected to be commissioned in a phased manner by 2021.
Raigarh-Pugalur-Trichur HVDC transmission route
The 1,850km-long 800kV Raigarh-Pugalur ultra-high-voltage DC (UHVDC) overhead transmission line originates from Raigarh in Chhattisgarh and passes through Maharashtra, Andhra Pradesh, and Telangana to terminate at Pugalur in Tamil Nadu.
The 320kV Pugalur-Thrissur HVDC stretches for approximately 200km from Pugalur to Trichur in Kerala. The line will comprise approximately 170km of overhead lines in Tamil Nadu and 30km of underground lines in Kerala.
Raigarh-Pugalur-Trichur transmission system
The HVDC transmission system will transfer 4GW and 2GW of electricity to the states of Tamil Nadu and Kerala respectively.
The project involves 800kV, 6,000MW inverter/converter terminals at Raigarh and Pugalur, as well as 320kV, 2,000MW inverter/converter terminals at Pugalur and North Trichur.
The 2,000MW terminal stations will incorporate VSC-based HVDC technology instead of conventional HVDC technology.
Cross-linked polyethylene (XLPE) HVDC cables are being used for the underground section of the Pugalur-Thrissur line.
The line will facilitate the long-distance transmission of bulk power generated by independent power producers (IPPs) including Jindal, GMR, and Lanco in Chhattisgarh. The HVDC link will transmit enough electricity to meet the electricity needs of more than 80 million people in south India.
The bipolar line will also be capable of transmitting surplus renewable energy from south India to north India.
PGCIL entered a loan agreement of £400m ($500m) with the Asian Development Bank (ADB) for the Raigarh-Pugalur-Trichur HVDC transmission project in February 2017.
BHEL, in consortium with ABB, was contracted for the execution of the Raigarh-Pugalur 800kV HVDC transmission system in the fourth quarter of 2016. The total contract value was estimated to be £660m ($840m).
ABB’s share of the contract value was £502m ($640m). It was responsible for the design, engineering and installation of the 800kV UHVDC system as well as the supply of major equipment of the complete UHVDC stations that include transformers, converter valves, cooling systems, as well as the control and protection technology.
A consortium of Siemens and Sumitomo Electric was awarded a contract worth £415m ($520m) to supply the Pugalur-Trichur HVDC transmission system featuring the voltage-sourced converter (VSC) technology in March 2017.
Sumitomo Electric was to supply a total of 128km of XLPE HVDC cables comprising four cables for a route of 32km each, while Siemens was responsible for the design, engineering, installation, and commissioning of the 320kV HVDC link as well as for the supply of major equipment for the 2,000MW HVDC stations, including converter valves, transformers, cooling systems, and control and protection technology.