Users expect reliable operation of the surge arrester during overvoltages, which may originate from a switching process or a lightning discharge. The necessary conditions to guarantee these expectations are: appropriate construction of the surge arrester, its production being maintained in accordance with technical standards, and a positive results of the type test. The recipient, especially when purchasing large quantities of the product, can check the final quality of the product through selective testing of samples from the market in order to find the best supplier. This manuscript specifies the basic parameters of low-voltage (LV) surge arresters of four manufacturers. Basic electrical parameters, i.e. leakage current and reference voltage before and after the discharge current of 8 µs /20 µs, were determined for 10 randomly selected surge arresters of each manufacturer. Moreover one sample of each varistor batches was aged by 50 simulated lightning strikes. The obtained results of structural analysis indicate that the crystal structure of the varistor materials changes after ageing process, affecting its electrical properties. The proposed research methodology can be employed as a basis for forecasting the stability of the arrester parameters under operating conditions.
The article discusses the issue of measuring and assessing the features of power line tower earthings using fast-changing waveform. The study analyses the effect of impulse front time and the line span length on errors made during these measurements using impulse meters. It has been found that the assessment conditions similar to the static measurement results occur for the use of 4 s current impulses and such procedure is useful for evaluating power line tower earthings. Streszczenie. W artykułe omówiono zasady pomiaru i zasady oceny uziemień słupów linii elektroenergetycznych przy użyciu udarów szybkozmiennych.oraz wpływ czasu czoła tych udarów oraz długości przęsła na dokładność pomiarów. Stwierdzono, że warunki oceny najbardziej zbliżone do wyników otrzymywanych przy pomiarach statycznych sugerowanych przez przepisy normalizacyjne występują przy udarach o czasie czoła 4 s. (Wpływ długości przęsła i czasu czoła udaru na dokładność pomiarów uziemień słupów linii elektroenergetycznych)
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