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Information × Registration Number 0221U102008, 0115U004699 , R & D reports Title Analysis of overvoltages in electrical networks and operating modes of measuring current and voltage transformers in this conditions popup.stage_title Head Yatseiko Andriy Ya., Кандидат технічних наук Registration Date 27-01-2021 Organization Lviv Polytechnic National University popup.description2 The calculation schemes are created and the modes of current transformers for opening the circuits of their secondary windings are analyzed, taking into account the losses of active power in their magnetic conductors. For current transformers, the expediency of creating and applying special protection to limit these overvoltages to the level of 1000 V is substantiated. The results of studies of transients during breakage of secondary circuits of different types of current transformers for 10–750 kV networks have established that in most cases the values of the first peaks of secondary voltages significantly exceed their established amplitudes. The magnitudes of the first surge peaks are especially dangerous for insulation, and steady-state voltages, due to their duration - for substation service personnel. A study of the influence of the mode of operation of the power grid on the multiplicity of arc, switching and ferroresonant overvoltages is performed. Based on the obtained results, it is shown that the multiplicities of overvoltages can exceed the values of test voltages for insulation of electrical equipment. A significant positive effect is given by grounding the neutral due to resistive resistance. For the studied electrical networks, either resistive neutral grounding or a combination of resonant and resistive grounding can be recommended. Product Description popup.authors popup.nrat_date 2021-01-27 Close