PROPAGATION OF LIGHTNING OVERVOLTAGES ACROSS MV/LV SUBSTATION – MEASUREMENTS AND MODELLING.

This paper presents measurement results of lightning overvoltages propagation across MV/LV substation and co-existent grounding system. Real substation which supply television broadcaster was used for tests. It’s one of few which work for TV Broadcasting Centre. On the TV area 30m high transceiver tower is placed. The risk of direct lightning strike is high. Major part of the MV/LV substation is 630kVA, 6/0.4kV, Dyn5 transformer. The results of these measurements were used to create transformer patch model. It base on measured frequency spectrum of MV/LV substation and circular convolution in frequency domain. Typical model of transformer was improved by created patch model. As a typical model it can be used any well-known transformer model. Created model was implemented to ATP/EMTP simulation program.