ince water treatment and water and sewage facilities have multiple buildings on a large site, they are easily affected by lightning surges because of the potential difference between grounds.
In particular, power lines and signal lines such as level switches and liquid level relays are wired outdoors, so they are easily affected by lightning surges. In the case of unmanned facilities, if the breaker is triggered by lightning surge even though there is no load abnormality, workers have to go to the site to restore the breaker.