Online catenary anti-icing technique for electric railways employing direct feeding systems

Catenary icing seriously affects the safety and reliability of the traction power supply systems of electric railways. To prevent icing damage without interrupting normal train traffic, an online anti-icing technique using the Joule-effect is presented. In this scheme, anti-icing current flows are adjusted over the entire catenary in accordance with not only environmental parameters, but also traction network voltage requirements. Determination of the requisite anti-icing current is based on a circuit analysis of a direct feeding system. The viability of the technique for a direct feeding system is demonstrated by simulation and experimental results in terms of both its thermal and electrical aspects. It is shown that the anti-icing system does not affect line protection operation under normal operational and various fault conditions, and requires no adjustment of the settings of the protective relays.