1. Renewal Construction of Hitachinaka City Waterworks Utility, Kamitsubo Water Purification Plant
The Kamitsubo Water Purification Plant is capable of supplying 38,100 m3 of water per day and accounts for 70% of the demand for the entire city of Hitachinaka, Ibaraki Prefecture. The plant entered use in 1965, and a project was launched to build a new water purification plant due to deterioration and seismic resistance measures.
With this new construction, roughly 200 high-voltage panels, power control panels, auxiliary relay panels, local panels, controller panels, and remote-monitoring units were delivered for the central monitoring facility, receiving and transforming/non-utility generation facility, sedimentation basin facility, filtration facility, dosing facility, water distribution pump facility, wastewater treatment facility, instrumentation facility, and the remote monitoring facility, with operation started in February 2022. The key features are as follows.
- In order to directly distribute water within the city with the water distribution pump at the new water purification plant, a control circuit was built to be able to promptly restart during a momentary power failure, and the decrease in water distribution pressure was minimized.
- Reliability was increased by setting up redundancies for the controller and control local area network (LAN).
- The number of cables has been reduced by using FL-net* for signal transmission and reception with the machinery panels and implementing input-output devices in the auxiliary relay panels to conserve resources.