Use of two tier gantry - aninnovative approach to mitigate row issues in transmission lines near terminating station

A number of transmission lines have been constructed across India from north to south and east to west to evacuate power from different parts of the country in the last few years. Transmission line system with voltages ranging from 66kV to 1200kV have been designed and constructed in the last few years. There have been a number of occasions where high voltage line such as 765kV D/C line has to cross another high voltage line and to make crossing arrangements, availability of space to erect tower sometimes is not adequate. This situation possesses a big challenge and demands to design and develop a special kind of tower. Furthermore, there have been numerous occasions when lines are to be terminated at substations with very limited available corridor/severe space crunch as already many existing lines are terminating at the substation. These lines occupy most of the corridor and there is hardly any space left to accommodate any new line. In one of the case, two400 kV D/C lines were required to be terminated in a substation with corridor availability for one line only from the front side. The second line was to be terminated from other side but the corridor was blocked due to development of a residential colony. Due to the severe space crunch near substation,two-tier gantry was used as an innovative measure to terminate both double circuit lines from one side through a Multi-circuit tower.The paper covers in salient design aspects and use of two tier gantry for site specific requirement.