Himatnagar is supplied by Uttar Gujarat Vij Company Limited, UGVCL, the GUVNL distribution company for north Gujarat. The town is also the seat of one of UGVCL's four circles: the Himatnagar Circle, which sits alongside the Mehsana, Sabarmati and Palanpur circles. UGVCL's own Himatnagar Circle tender notices list a Himatnagar Division with Himatnagar Town, Himatnagar Rural, Mehtapura and Gambhoi sub-divisions under it. Which of those holds your file depends on your connection, and your bill names it.
Get the licensee right before anything is filed. Torrent Power distributes in Ahmedabad, Gandhinagar and Surat city, not in Sabarkantha. DGVCL covers south Gujarat, MGVCL central Gujarat and PGVCL Saurashtra and Kutch. A Himatnagar quotation that names any of them was written for another town, and an application lodged with the wrong company simply sits there.
The rules come from the Gujarat Electricity Regulatory Commission. Rooftop capacity is limited to your sanctioned load, residential, commercial, industrial and agricultural consumers can all apply, and exported units are set against imported units in each billing cycle. How any leftover credit is settled follows the GERC order in force on your commissioning date.