generating power u2014 based on the type of technology and given area u2014 that define the size of transformation unit for more economical project the higher low voltage value and larger possible transformation unit is the one to be chosen if possible when making decision to maximize the ac power transfer efficiency throughout the energy collection system not to be less than 98 hence the losses have to be restricted not to be more than 2 there are two major sources of losses in the energy collection system at the initial stage of preparation of specification of transformers there must be an emphasis on the load losses at full load at temperature of 75 c amp 120 c to be less than 1 of the rated capacity of the transformer and the no load loss should not exceed 0 1 these values must be confirmed during the testing of transformers at factory fat during real operation of solar pv system the fully loading hours on transformer can be experienced only at mid of summer days but in general average loading ratio is much lower and could equal to the capacity factor of solar project which is around 25 hence the average losses is lower than 1 say it is 0 75 the losses in the cables are proportional to the square of the current the main ht cable is double circuit and designed to have double of the normal capacity for meeting contingencies and to have very low resistance which produces very low losses at rated power add to that the average loading is around 25 of the rated.