بر نقش مبدل های ترانسفورماتور و مانع از افزایش ولتاژ ناشی از رعد و برق در شبکه های توزیع پیچیده

This paper presents a study of overvoltages caused by cloud-to-ground lightning strikes on loads connected to a complex low-voltage distribution network. The importance of the transformer grounding in the resulting load overvoltages is discussed for two different lightning events. These events emphasize either the induced-voltage component or the surge transference through the distribution transformer as the main source of overvoltages on the connected loads. A brief discussion is also presented on the efficiency of low-voltage surge arresters in protecting loads connected to complex low-voltage networks. The obtained results indicate that the effectiveness of improving the transformer grounding and of installing surge arresters at specific points of the low-voltage network is limited in terms of load protection if a complex network topology is considered. In some cases, especially for a lightning strike close to the low-voltage line, improving the transformer grounding can even increase load overvoltages.