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Smartcount Surge Arrester Monitor
- Leakage and impulse current monitor
- Measurement of impulse amplitudes, peak current and resistive current according to IEC60099-5, Method B2
- Temperature compensation
- Data logging up to 18 years
- Quick and comfartable data download to Android smartphone using NFC
- Analysis of results on website or PC – critical threshold and alert function
- No external power supply required
- Easy installation, maintenance-free, waterproof, rugged and reliable
A permanently applied voltage causes a continuous leakage current in surge arresters without spark gaps (metal oxide arresters). While capacitive current component is dominating with ap- plied continuous operating voltage, the resistive component (A to kA range) is prevailing in case of temporary overvoltages or discharge processes. Causes a resistive leakage current, due to overload and/or ageing of the metal oxide varistor, such a big amount of heat, which no longer can be dissipated via the arrester surface, the arrester will be destroyed (thermal run- away).
The following problems may occur during the operating time of the arrester:
- Frequent current impulses with high amplitude or energy-rich discharge processes lead to irreversible changes of the varistor characteristic (degradation). The leakage current in- creases subsequently.
- A change in the voltage distribution caused by external pollution of the arrester housing may result in an increased power dissipation in the metal oxide varistor stack.
A rise of varistor temperature will be the consequence from increased leakage current or in- creased power dissipation caused by such operating conditions. This temperature increase will be enhanced by the negative temperature coefficient of the metal oxide varistors.
