Section 2(1)(ii) in The Delhi Electricity Regulatory Commission (Terms and Conditions for Determination of Transmission Tariff) Regulations, 2011
(ii)"Transmission System" means the system consisting mainly of extra high voltage electric lines and associated equipments and substations having design voltage higher than 66 KV including any other system of lower voltage as the Transfer Scheme or the Commission may specifically recognise, owned or controlled by the Transmission Licensee, and used for the purposes of the transportation of electricity between the switchyards of two Generating Stations or from the switchyard of a Generating Station to a substation, or between substations, or to or from any external interconnection and includes all bays/equipment up to the interconnection with the Distribution System, and any plant, apparatus and meters owned or used in connection with the transmission of electricity, but shall not include any part of a Distribution System.