Benefits and Problems raised by Multi-circuit Overhead Lines Operation

The paper presents a short analysis of benefits and disadvantages of multi-circuit overhead lines operation. Nowadays, the problem to build a new overhead line is a very difficult one because of land cost and different properties crossed by it, environmental impact, opposition of large public etc. Therefore, the solution to use same tower to support many circuits, with same or different rated voltage, also for AC and DC systems is very attractive. The main advantage is that of use of a narrow corridor to transmit a large amount of power. But other problems must be solved in order to make this type of line working properly, from solving the mutual influence of the circuits to lightning protection and up to the low frequency electromagnetic fields profile recorded near to ground.