Power transmission devices should be low loss and maximum efficiency.

I agree with Mondal but techno economical aspect is also very important so low losses and max efficiency with minimum investment costs in the period of full working time.

I think first criterion should be the transmission voltage, at what voltage level you want to transmit the power, on this, rating of the equipment associated with the transmission of the power like insulators, conductors, insulation coordination of various devices which are involved in transmission process can be obtained. The second criterion should be the type of transmission HVAC or HVDC .

I agree with Mondal and Nikolovski. the objective may be transmitting power from one point to the other which need to be technically and economically feasible. Technical solutions are evaluated by using sub-ojective indices (low loss, efficiency etc) to help in decision-making process. however, economic aspect determines what solution is viable looking into benefit vs cost over the life span of the solution. As a result, economic indicators like least life cycle cost (LLCC) are used to determine the economic viability of a solution prior to making infrastructure investment.

considering transmission lines, it is always high voltage either by HVAC or HVDC . High voltage because of expected quantity of losses during transmission , which also depends on the length of the transmission line.

Again, this high voltage will depend on the choice and type of insulation string. To have values for money, cost is the bottom line, as everything from the beginning to the end of power transmission is expensive.