Design a transmission system to carry power from wind farms in North Dakota to the state of Illinois (about 1200 km). The system should handle Illinois’s summer time electricity demand of 42GW. Land for transmission towers is at a premium, so the system uses very high voltage (V_RMS = 765 kV).Assume that the electricity is transmitted as ordinary alternating current, although in practice three-phase power would be used. Assume that each tower can carry 36 aluminum cables (nine lines, each consisting of four conductors separated by non conducting spacers). The conductors are 750 mm² in cross section. How many separate strings of transmission towers are needed if the transmission losses are to be kept below 5%? Assume a purely resistive load.