A Ringed Non-Uniform Network: How to Raise its Efficiency
As distinct from radial electric power lines, in closed loops the consumers are fed from two sides. This is advantageous from the viewpoint of supply reliability, power quality and its losses; however, these are the least only when a loop is uniform, which is not always met in practice. In a non-uniform loop a circulating current flows, and the losses increase proportionally to its square. To reduce losses in such a non-uniform loop, the circulating current should be eliminated. For this purpose a booster transformer can be used. The voltage of such a transformer is known to be in quadrature to the phase voltage; the present consideration has shown that such orientation of the opposing voltage gives the best results only when all loads in the loop are active, otherwise the angle of opposing voltage should be regulated. The voltage value should also be regulated depending on the load. Another technique consists in introducing a complementary reactance into the terminal branches. Such reactance should be regulated if loads are changing in time disproportionately with respect to each other. The best results are achieved when all loop node loads have the same cosφ. If the complementary reactance calculated at one end of the loop is positive, then that calculated at the second end of the loop will be negative, and vice versa. The appropriate choice can be made, in particular, involving both loop terminals.
Vanags, A. (2007). Elektriskie tīkli un sistēmas, I daļa. Rīga: RTU (6. nod.).
ENK5 - CT 2001 - 00522. DISPOWER. Distributed generation with high penetration of renewable energy sources. Structure and data concerning electrical grids for Italy, Germany, Spain, UK, Poland.www.iset.Uni-kassel.de/dispower