RAL300 Ideal upgrade for inaccessible location Modbus Turbine Control
Industry : Water
Client : Water Utility Company
Product : RAM / RAL300
Summary
RIFT was approached in 2023 to assist in supporting the drive towards net zero carbon emissions in relation to variable turbine control. A number of existingly actuated valves had been identified as potential areas for improvement. Energy efficiency in both process and in terms of actual equipment are both key drivers in the moves towards net zero. RIFT was happy to be called in to help support this project.
Overview
A remote water industry site, controlling flows to a series of electricity generation turbines in a small reservoir. The site has existing infrastructure and a PLC unit communicating with various on site equipment through Modbus. The site suffers from limited electrical supply (currently supplied by an on site generator), so overall energy efficiency of the site was important. Generated supply was not always available to run site equipment. Variable control on a series of rising stem gate valves was currently in place, but the accuracy and efficiency of the installed solution was not sufficient, particularly when coupled with the energy being used within the process. RIFT was asked to provide control for the gate valves on site utilising very low energy. The site battery backup to enable the generators to be started was not sufficient to power traditional actuators. Manual intervention was required on site to manually open and close valves in order to start or maintain the flows.
Challenge
It is not uncommon for water industry locations to be far away from traditional infrastructure. The trial site in question was both high in hills and a long way from mains power. The site power was supplied by a combination of internal generation from the turbines (when running) or battery backup / diesel generator when the turbines were not running. The overall energy footprint of the site therefore became very important. Although not a massive site, the water reservoir management providing an overflow for other water systems comprising part of the overall water management strategy.
As a test site running under a small PLC being able to send and receive accurate information to actuators, adjusting the input flow levels to generator turbines, while maintaining and adjusting the water levels in the main storage system, the site faced significant details. When RIFT visited the site, it could be noted that staff were required nearly 24 hours a day to keep the site running correctly.
Tight locations, with little space, low power and a requirement to operate for prolonged periods preferably without maintenance all added to the site challenges.
Solution
While RIFT initially installed 4 RAM actuators in multi-turn mode to operate the existing gate valves, it was found that with the water pressures involved in the pipeline, torques on the gate valve could exceed 100Nm. Substituting new RAL300 actuators onto the 4 gate valves, and connecting them to the PLC through RS485 for Modbus communication became a simple but efficient solution. Being able to provide feedback through Modbus and moving accurately to different positions based on the PLC controls allowed the facility to become almost completely autonomous. This change in staffing significantly reduced the costs associated with the site, while still seeing significant improvements in the overall site performance. The 4 RAL300s run off a 24W power supply, which is easily accommodated within the battery backup system, reducing the sites reliance on diesel generators to come online when needed. The ample torque overhead in the RAL300 allowed for dynamic torque profiles to be configured which could deal which significant changes in the torque required to operate the gate valve, especially when under significant pressure.
