A new monitoring system for metal oxide surge arresters

For on-line monitoring of MO-surge arresters a system has been developed, that monitors and evaluates the performance characteristics of surge arresters. During normal operation without surge events, the peak values of the leakage currents and line voltages as well as the ambient temperature are measured and stored in periodic time intervals. In larger time intervals one period of all current and voltage signals is sampled in a high temporal resolution and stored. These data are used for calculation of the harmonics component in the leakage currents. In case of surge events, the peak values and polarities of the impulse currents are measured and classified