In this paper, we consider the identification of a smart grid network topology by means of admittance measurements performed at the network nodes. We show how the application of the transmission line theory allows the identification of the node-to-node connections. Thereby, a topology identification algorithm is presented. The identification error due to the network noise is reduced by performing repeated measurements, either at different time instants or over a set of frequencies, at each network node. The information is then fused by means of the total least square regression technique, which is also compared to a simpler estimator. A thorough analysis of the results is then presented, which shows good reliability of the proposed algorithm.