Investigating the factors affecting the transient overvoltages caused by lightning in the low-voltage network and the role of the SPD installed in the substation in protecting the network

Document Type : Power Article

Authors

1 Electrical and computer engineering, Semnan University.

2 Department of electrical engineering, Faculty of electrical & computer engineering, Semnan university

Abstract

Surges caused by direct or indirect lightning strikes on distribution networks threaten network equipment and consumers. Several parameters affect the intensity of transient over-voltages caused by lightning (surge), and significant studies have been done in this field. However, the effect of some parameters on the surges in the low-voltage network has not been investigated. Among these cases, we can mention using self-supporting cable instead of open wire and the effect of neutrals distributed along the low-voltage feeder. Therefore, in this article, the role of the two mentioned factors on the intensity of transient over-voltages in the low-voltage distribution network is investigated.

The presence of a surge protective device (SPD) in the secondary of the distribution transformer has a significant effect on the protection of the distribution transformer against direct and indirect lightning strikes to the low-voltage distribution network. But so far, some of the effects of this SPD on surges at the input of low-voltage consumers have not been investigated. Therefore, in this article, the positive and negative role of the SPD installed in the distribution substation on the consumers is investigated. Based on the investigations, it is determined that the SPD installed at the substation has a positive or negative effect on which subscribers and under what conditions. Based on the studies, it was concluded that the presence of SPD at the distribution substation reduces the intensity of the surge for some subscribers and increases the intensity of the surge for others.

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