In order to strengthen the electricity transmission and distribution system within the country, the construction of 400 kV Inaruwa Substation has been completed in Bhokraha Narsingh Rural Municipality-4 of Sunsari. The construction of the second largest 400 kV substation of Nepal, based on the Gas Insulated System (GIS), was completed and operated (charged) on Monday.

For east-west electricity supply and electricity trade with India, Dhalkebar is the first automatic substation in the country and Inaruwa is the second largest substation with GIS technology. Another substation of 220/132/33 kV has been completed in Inaruwa.

The 400/220 kV Inaruwa Substation constructed under the Hetauda-Dhalkebar-Inaruwa 400 kV Substation Expansion Project has three power transformers of 315 MVA capacity. So, the total capacity is 945 MVA. After the construction of the Inaruwa-Dhalkebar 400 kV transmission line is completed, around 4000 MW of electricity can be exchanged from the Inrauwa Substation.

Kulman Ghising, managing director of Nepal Electricity Authority (NEA), said that the Inrauwa Substation is a backbone for the transmission of electricity produced by hydropower projects in various districts of Koshi Province, for local consumption and for export to India.

"The construction of the Inaruwa Substation has to be completed immediately to provide more power to the industries in the Morang-Sunsari Industrial Corridor and to make the supply reliable and qualitative. We are ready to solve the problems in construction of the substation immediately," he said. “The 220 kV transmission line can be charged to 220 kV, then resources will be available for power supply in the area, which will make the system reliable.”

The Inruwa Substation is considered important to provide more electricity to the industries in the Morang-Sunsari industrial corridor and to make the supply reliable and quality.

The electricity generated from the hydropower projects constructed or to be constructed on the Arun and Tamor Rivers and their tributaries will be connected to the Inaruwa Substation through the Koshi Corridor 220 kV transmission line.

The construction of the Inrauwa-Basantapur-Tumlingtar section of the Koshi Corridor has been completed, while the Basantapur-Dhungesanghu (Taplejung) section is under construction. Similarly, the Tumlingtar-Shitalpati 220 kV transmission line project is also under construction. The construction of the Arun Hub-Inrauwa 400 KV transmission line has been proposed.

Shukra Devkota, the project head, said that the Inaruwa Substation has been built in such a way that it can be further expanded in the future. The construction of the substation was affected because the equipment and technicians could not come due to the floods in the Terai during the rainy season, the restrictions and prohibitions imposed for the prevention and control of the global spread of Covid-19.

Devkota, the project head, mentioned that the flood that occurred in the substation construction area in mid-November 2021, damaged the equipment and had to be re-imported, which caused some delay in the construction.

Under the project, 400 KV Dhalkebar Substation has been completed and is in operation, while Hetauda Substation is in the final stage of construction. A contract agreement was signed in mid-January 2019 for the construction of Inaruwa and Hetauda Substations.

The estimated cost of Inaruwa Substation, which was built with the investment of the Nepal government and the NEA, is US $ 14.3 million.