The paper puts forward a recent practical issue
which has never been addressed before that is associated with
resonant grounded networks fed from multiple independent
transformers and located in the same substation. This situation
is common when the network is not initially designed as a
resonant grounding network and the intention of using resonant
grounding scheme is to reduce the risk of bushfire due to ground
faults. In these situations, undesirable over-voltages are noticed
on several practical healthy networks when faults occur on other
networks. The paper analyses this phenomenon and investigates
the factors impacting these unexpected over-voltages to help
industries associated with such phenomenon to achieve the best
strategies to avoid it.