Equivalent Circuit of Pole-Mounted Distribution Transformer for Analysis of Lightning Overvoltages

摘要

Pole-mounted transformers on a power distribution line are vulnerable to lightning overvoltages, and their response draws great concern. The authors have developed an equivalent circuit of a distribution transformer seen from the primary side. In this paper, an equivalent circuit of a transformer whereby one can also copes with its influence on the overvoltage on the low-voltage line and transfer voltages is presented based on modal analysis of measured admittance. The validity of the equivalent circuit is demonstrated by comparison with measurements. The response of transformers having various rated power to the impulse voltages is investigated based on experimental results.