Abstract
Operational experiences with IEC 61850 process bus and low-power instrument transformers (LPITs) from eight digital substations (DS) in Norway are presented in this paper. The eight DSs have been installed at both transmission system operator (TSO) and distribution system operators (DSOs). The operational experience in these digital stations has been mostly satisfactory. However, some problems have been identified, which will be discussed in this paper. These include challenges with implementing LPIT technology and time synchronization of intelligent