CEA Proposes Reconductoring Of ISTS Transmission Lines Under RTM Mode

The Central Electricity Authority (CEA) issued a draft discussion paper on reconductoring ISTS (Inter-State Transmission System) lines. The central authority said that this could augment power transmission capacity and standardize the system. 

The government agency asked the stakeholders and the general public to send in their objections and comments on the same by July 17, 2023. It comes after directions were issued during the 10th meeting of the National Committee on Transmission (NCT) to prepare a base paper for identifying implementation modalities for reconductoring works to standardize or simply the decisions in this regard.

“To meet the changing demand and generation scenario, the transmission system needs to be expanded and strengthened. The strengthening may require the building of new transmission lines and substations or the augmentation of existing transmission/transformation capacity by suitable means. One of the methods to preserve the right of way (RoW) and increase the transmission capacity of a line is reconductoring with high capacity high-performance conductors,” the CEA paper said.

Reconductoring refers to stringing new conductors on existing towers using the same RoW to increase the thermal capacity of transmission lines. It may require modification or replacement of some towers in cases where their load-bearing capacity is insufficient. The provision of reconductoring might also require replacing terminal bay equipment with high-rating equipment commensurate with the rating of new conductors. 

The CEA paper said that the Central Transmission Utility (CTU) is responsible for developing the ISTS network. It should draw a proposal for new elements in the ISTS, including reconductoring after consultations with different stakeholders.

The paper says the new conductors should have higher continuous operating temperatures and ampacity than the existing ones. The physical design parameters like sag, swing and diameter, among others, of the new conductors should be similar to or better to the existing conductors to the transmission lines, it said.

It also said that the short-circuit current rating of the new conductor should not be less than the short-circuit rating of the existing conductors. It also talked about the need to ensure the whole planning of the tower’s healthiness. “In case any tower reinforcement is needed, the same can be taken up in conjunction with reconductoring,” the paper said.

The CEA paper also discussed the pros and cons of reconductoring in two modes: one with the Regulated Tariff Mechanism (RTM) and the other one under the Tariff-based Competitive Bidding (TBCB) mode. It, however, proposed roping in the RTM route for reconductoring of transmission lines.

“In the period of the useful life of transmission system, to avoid technical, commercial and operational issues in reconductoring of transmission line, it would be prudent to allocate the scheme to the existing owner (TSP) through RTM route,” it said.

It also added, “The transmission system implemented under TBCB would be handed over to CTUIL, its successors, or an agency as decided by the Central Government after 35 years (as per SBD), and the asset would be again bid out. If required, fresh bidding may include reconductoring and strengthening at this stage.”