Three-dimensional modeling on lightning induced overvoltage for photovoltaic arrays installed on mountain

Since the area of photovoltaic (PV) plant is much larger than conventional power plant, the PV system is exposed to lightning strike at a high risk. A three-dimensional model for the electromagnetic transient in PV array is proposed. Taking lightning channel geometry into account, the magnetic field nearby is derived; the mutual coupling between metal frame of PV panel and thin conductor is then developed. The proposed model is compared with previous methods and validated by experimental results. It suggests that the induced voltage is governed by the magnetic field in essence, and the influences of PV oblique angle, the lightning strike point are discussed in detail. The presence of encapsulated metal frame can produce an opposite magnetic field with respect to original lightning channel and the reduction factor can reach up to 2.58. Furthermore, three installation modes for PV array on mountain terrain are compared. Since part of magnetic flux cross from the wiring-loop surface to the other side and the total flux would decrease, the induced voltage for that installed along the hill ridge is the lowest. As the increase of hillside angle, the induced voltage decays drastically. The results could provide a guideline for lightning protection of PV system on mountain terrain. (C) 2020 Elsevier Ltd. All rights reserved.