Kathmandu, November 7, 2024 — The Chilime-Trishuli 220 kV transmission line has been brought into operation. Electricity began flowing from the 28-kilometer line connecting the Chilime Hub Substation in Thambuchet, Aamachodingmo Rural Municipality, Rasuwa, to the Trishuli Three B Hub Substation in Pahirebensi, Kispang Rural Municipality, Nuwakot, at 7:30 pm on Wednesday.
Alongside, the Chilime Hub Substation constructed under the same project was also charged on Wednesday. The substation houses two 220/132 kV transformers, each with a 160 MVA capacity, totaling 320 MVA, along with 132/33 kV transformers of 50 MVA capacity. The Trishuli Three B Hub 220 kV substation under this project was already in operation.
The Chilime-Trishuli 220 kV transmission line, designed to integrate approximately 1,200 MW of electricity produced by hydropower projects on the Trishuli River and its tributaries into the national grid, can carry up to 1,200 MW of power.
The estimated cost of the Chilime-Trishuli project is NPR 3.62 billion, funded by the Government of Nepal, Nepal Electricity Authority (NEA), and a grant from the German Development Bank (KfW). Additionally, the European Investment Bank (EIB), established by the European Union, provided a concessional loan.
Thark Bahadur Thapa, Director of the NEA High Voltage Grid Department, stated that with the construction and operation of the transmission line and substation, electricity produced by hydropower projects in the area can now be connected at any time.
Initially, power generated from the 111 MW Rasuwagadhi, 42.5 MW Sanjen, and 14.8 MW Sanjen hydropower projects, led by Chilime Hydropower, will be connected to the Chilime Hub Substation. The Rasuwagadhi and Sanjen projects are in the final stages of construction and will begin power production soon. Construction of the transmission line was completed with employees and contractors working around the clock, including during the public holidays of Dashain and Tihar.
A total of 76 towers were constructed for the 28-kilometer transmission line, which spans areas ranging from 680 meters to 2,600 meters above sea level. Thirty-three towers had to be built in areas with no access roads, necessitating the construction of more than 20 kilometers of new access roads for the project. Construction materials for the towers were transported by helicopter to some locations.
The project faced several challenges due to the geographically remote and mountainous terrain, with steep cliffs and lack of road access, requiring materials like stones, sand, tower components, and water to be transported by hand or mule. Issues such as landslides, land use within forest areas, local opposition, COVID-19 impacts, and adverse weather conditions in the mountainous region affected the construction progress.
A section of the line stretching 1,235 meters from Tiru to Siruchet in Uttargaya Rural Municipality-1 was strung using drones to cross the Mailung River (Mailung Crossing).
The Chilime-Mailung section of the transmission line is 20 kilometers and is built as a double-circuit line, while the Mailung-Trishuli Three B Hub section is an 8-kilometer multi-circuit line. The multi-circuit line was constructed to connect the 216 MW Upper Trishuli-1 Hydropower Project, led by Korean companies. Upper Trishuli-1 will cover 60% of the cost incurred in constructing the multi-circuit line.
A contract agreement for the construction of the transmission line and substations was signed with the Chinese company Pinggao Group of Companies in November 2017, with implementation starting in December 2017.
