Considerations on the characteristic impedance of periodically grounded multiconductor transmission lines

The paper deals with the evaluation of the characteristic impedance of a multiconductor transmission line with one conductor periodically grounded. The topic, even if not adequately discussed in literature, has a relevant application in the analysis of the role of the shield wire in power lines, in order to quantify the mitigation of induced overvoltages. The problem is here modelled, leading to a nonsymmetric algebraic Riccati equation, that is solved with both a factorization and an iterative method. The solution is presented in a practical case and the efficiency of the methods are discussed.