A new lossless circuit balancing the MV distribution systems from insulated shield wires of HV lines

Three-phase scheme shield wire lines (MV lines obtained by isolating 2 shield wires of an HV transmission line) are intrinsically unbalanced. Even though the load supplied is balanced, negative sequence components of the voltage are originated by this asymmetry. Balancing means are necessary in order to contain these components to tolerable values. The paper presents a new balancing circuit, made of static, lossless, low cost components. The circuit has important advantages with respect to the compensating means proposed and applied in the past. In particular its application, in addition to the balancing effect, enables reduction of the voltage drop and does not cause any increase of the active power losses. The paper presents the circuit in two different forms together with the principles that justify its genesis.