Case studies(Introduction examples)

Lightning protection for water treatment facilities

Water treatment facilities on large sites need lightning surge protection.

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.

Dangers if no measures are taken
  • Stoppage or malfunction of facilities and equipment due to lightning surge
  • Stoppage of operations until facilities are restored
  • Causes stoppage of water level measurement, incorrect display of water level measurement, and trouble during disasters

Lightning protection points for water treatment facilities

Countermeasure points
The basic measures are not much different from those for other devices, but SPDs and surge arresters are installed at each of the multiple building entrances. SPD for power supply and SPD for signal lines are installed for communication and signals. A UPS should also be installed on the power supply in case of unexpected power outages due to lightning strikes.

When a breaker trips due to a lightning surge even though the load is not abnormal, it may be difficult to turn the breaker back on because the outlet is unmanned. By installing a reset breaker in an unmanned facility such as a discharge outlet, it is possible to determine whether the breaker has tripped due to a lightning surge or a load error, and automatically turn the breaker back on only in the case of a lightning surge, thereby reducing the burden on workers.

Installation example

Lightning protection products for water treatment facilities