Power Grid Corporation of India has announced that Pole-1 of the HVDC bipole link between Raigarh (Chhattisgarh) and Pugalur (Tamil Nadu) was put in commercial operations on September 6, 2020.
PGCIL has elaborated that the following assets have been put under commercial operations from the said date:
- +800kV 6,000-mw Raigarh (HVDC Station) – Pugalur (HVDC Station) HVDC link along with 1,500-mw (Pole-1) HVDC Terminal each at Raigarh (HVDC Station) and Pugalur (HVDC Station), and
- AC system strengthening at the Pugalur end, including 400kV Pugalur (HVDC Station) – Pugalur (existing) (Quad) D/C transmission line along with associated bays at Pugalur (HVDC Station) and existing Pugalur substation; and (ii) 400kV Pugalur (HVDC Station) – Arasur D/C transmission line along with associated bays at Pugalur (HVDC Station) and Arasur substation.
According to information available with T&D India, the entire 800kV Raigarh-Pugalur HVDC link is expected to be commissioned by December 2020.
The ground-breaking ceremony for this project was held in May 2017.
The 800kV Raigarh-Pugalur HVDC line will help India’s southern region importing power from the northern region. In view of the long distance, it was decided to go in for HVDC technology.
As far as HVDC Bipole-2 and the associated lines are concerned, the project is around 75 per cent complete. The AC lines, matching with Bipole-2, will be completed by December 2020.
The third component of the project is a 320kV HVDC line spanning 153 km and the VSC terminal. This is also expected to commission by December 2020.
The Raigarh-Pugalur bipolar link with a transfer capacity of 6,000 mw, will traverse around 1,750 km from Chhattisgarh to Tamil Nadu, passing through Maharashtra, Andhra Pradesh and Telangana, en route.
It may be noted that the 320kV HVDC line discussed above will connect Pugalur in Tamil Nadu to North Trichur in Kerala, and will have a transfer capacity of 2,000 mw. Because of severe right-of-way constraints in Kerala, it was decided to go in for VSC technology so that power could ultimately be transferred to Kerala.
It is very interesting to note that in this 320kV link between Tamil Nadu and Kerala, there are overhead lines up to the Kerala territory. Within Kerala, wherever RoW constraints were encountered, PGCIL has laid underground EHV cables. Of the 153 km of total length, underground cables accounted for some 27 km (all in Kerala).
Apart from HVDC, VSC technology and underground EHV cables were innovations that marked a departure from conventional technology for interregional lines.
Project partners
The 800kV 6,000-mw Raigarh-Pugalur, 800kV, HVDC system is based on LCC (line commutate converter) technology, while the 320kV 2,000-mw Pugalur- Thrissur system is based on VSC (voltage source converter) technology.
The 800kV part of the HVDC project has been contracted on ABB in consortium with BHEL, while the 320kV portion has been mandated upon Siemens.
Featured photograph shows a generic valve hall, which is a crucial component of any HVDC power transmission project. (Photo: Hitachi ABB Power Grids)
