Comparison of transmission losses and voltage drops of GIL(Gas Insulated transmission line) and overhead transmission lines

In a power system the loads are connected to the generation plants through transmission lines. The transmission lines are overhead and underground cables. From last forty years the new technology is included in the underground cable GIL. GIL has lot of advantages on underground cables and overhead transmission lines such as low transmission losses, less capacitive load, reliability, personal safety, same operation as overhead lines and with negligible electric aging. GIL can handle much more power than overhead lines due to his large conductor area. GIL is best for high voltages. GIL can be our future lines specially in big cities due to increasing population and size of big cities. In this paper the losses and voltage drops of same voltage rated overhead lines are compared to GIL lines. The simulation in PSCAD is done using the parameters of overhead and GIL lines of same rated voltages (230 KV, 345KV, 500KV, 765KV, 1100KV). The length of line is taken as 100km in both cases. The comparison graphs of percentage losses and voltage drops are plotted using MATLAB.