Aurora undertook a series of power system earthing studies for Windcare, for several new 11kV wind-turbine substations, in order to meet DNO approval. These studies included calculation of the earth potential rise (EPR), and touch and step voltages along with the tolerable limits for operational personnel.
One of the studies proved to be particularly challenging as with an initial EPR value of over 4000V was located in the middle of an Equestrian centre, and posed a significant risk to the animals. Aurora undertake detailed research into the tolerable step limits for horses, in order to make sure the animals were protected against unsafe step voltages – which were as low as 40V!
