A Case Study on the Risk Assessment for the Grass Carp Fish During a Lightning Strike to Nearby Distribution Tower and Some Suggestion on Protective Measures

Due to lightning strikes, electric current with high power density flows through the ground grid or driven rod of power distribution line towers to the soil, which may threaten the safety of aquatic organisms in nearby ponds. In engineering practice, there is a lack of an effective risk assessment method for aquatic organisms around earthing devices of power distribution networks under impulse current dissipation caused by lightning strikes. To solve this problem, a method to assess the safety of grass carp is proposed. First, based on a method of equivalent conduction, the conductivity of a typical grass carp is measured, and current threshold values causing different reactions in grass carp are observed and recorded. Then, the steps for risk assessment are given, with consideration given to the probability distribution characteristics of lightning current amplitude. Finally, some protective measures to reduce the threat of lightning current are given. The performances of different protection methods are analyzed based on a case in Foshan city. The results show that implementing protective measures can effectively reduce adverse reactions of grass carp in thunderstorm weather.