Overvoltage Protection Surveys – Based on the recommendations of IEC 60099-5, this survey evaluates and reports on the selection and application of surge arresters installed in substations, at overhead power lines, cables, transformers and motors.

The condition of the metal oxide surge arresters can be determined by using well-proven monitoring techniques to record and store the actual resistive component of the leakage current of the surge arresters.

Rated by IEC 60099-5 as the best field monitoring technique for Metal Oxide Surge Arresters, the measurements are automatically normalized to standard ambient temperature and the rated arrester voltage, based on recorded temperature and operating voltage during field measurements. Measurements performed under different conditions can thereby easily be compared.

The inspection of surge arresters is done on location and the tests are performed with the arresters in live operation, without the interruption of power distribution. The current monitoring equipment is used to trend the condition of all types of metal oxide surge arresters that are installed on an insulated base with one separate grounding system conductor.

Monitoring can be done either during periodic, transitory inspections or over a long period of time. In this way necessary information to determine the real service condition of the surge arresters is made available.