Operational experiences of active shielding systems for overhead HV lines

In the framework of reducing the impact of the electric system infrastructure, the paper presents the successful field application of the principle of active shielding of the magnetic field of HV overhead lines. Two plants have been deployed and are currently being operated since some years on a 132kV and a 400kV line. The solution to be used locally, where sensible targets exist or where it is hard to find free paths for new lines, minimizes the impact on the line structure. Two different control system solutions have been studied and applied to avoid any impact on the normal operation of the line. Both systems have been continuously operated for some years and have assured to keep the magnetic field at the sensible targets below the desired limits.