Lahan Substation with single busbar sytem, located at Lahan of Siraha district of Sagarmatha zone feeds power to Rajbiraj, Rupani, Jaljale and Bastipur. This substation is connected to Dhalkebar and Duhabi by 132kV double circuit line. This substation was commissioned in 1992 with 132/33 kV two number of 12.5 MVA transfomers. The Kusaha and Dhalkebar II bays were constructed in 1999. The line 2 is connected to Duhabi substation through Kusaha switching station In 2004, one12.5 MVA Transformer got damaged and was replaced by 10 MVA. The 10MVA Transformer was further upgraded to 20MVA in 2006. The existing12.5 MVA was replaced by new 63MVA Transformer in 2011.