Delivering power to wells in an underground water supply network is no easy task, which also turned out to be the reality for Strømmen Vandværk in Randers, Denmark. After much planning and consideration, the first well is now in place at Strømmen Vandværk and the ideal power solution has been chosen.
Obtaining a valuable overview
Prior to this, there was a comprehensive task of dividing the entire supply network into separate pressure zones. Initially, the network was split into four zones, each to have an inlet chamber established. The chamber will have an intelligent control valve mounted alongside an ultrasonic water meter, which will then measure the volume entering the pressure zone. This is very valuable information, as the network obtains a full overview of how much water enters a specific zone held against how much is actually consumed by the network customers – all relative to the specific time of day. This way, Strømmen Vandforsyning will be able to start establishing parameters for the pressure adjustments within the zone based on the collected network data. In other words, the pressure will be following the water demand, reducing the pressure when possible to the minimum service pressure promised to network customers.
This way of regulating the pressure can also be used actively for controlling pressure elsewhere in the pressure zone. There might be areas with great pressure losses when consumption is high, which can happen with old, internally overgrown pipes reducing the flow or if the piping is too narrow for the actual water demand. By logging data on flow and pressure in this critical area, the control valve can be programmed to regulate the pressure and keep it at a constant level within the area.
Having the control valve adjusting the pressure constantly is not only saving water and energy, but is also stabilising the overall pressure which has a direct positive impact on the pipeline system lifespan.
In the well, and alongside the control valve, a PLC (programmable logical computer) controller is mounted which communicates directly with the network’s SCADA system on a regular frequency. The network manager has an app installed on his smartphone which is connected to the SCADA system via the internet. This way, he is not dependent on being situated in the network’s control room to be able to monitor and control activities. Should a pipe burst be reported outside of hours, he is able to ask the control valve shut off the supply via the app, saving valuable time – and water. Data is exchanged between the valves and the SCADA system every other second, but this span might be adjusted to fit needs and future possibilities.
Both the controller and the valve need power to be able to work, and supplying this caused a bit of trouble for the project. Should the network be connected to a lamppost or traffic lights? How about a back-up battery supported by a water turbine to keep it charged? Or, would an entire power supply be necessary? Many scenarios and considerations later, the decisions was made to play it safe, and to have an own power supply established from the public network. When the system has been up and running for some time, it will be possible to analyse data from power use and to evaluate other sources such as solar cells, water turbines etc.
Establishing the first well
The first section well has entered the ground on the spot marked with “4” on the map over the water supply area, and work is now initiated to connect to the zone’s main lines. The well is placed right next to the water pipe and is connected via a by-pass. This assures continuous supply for the area, even when the well needs to be taken out for maintenance.
Strømmen Vandværk has never worked with pressure zones or DMA strategies before, which means that there is a great deal of learning and experiencing. The first well is just the beginning of a massive knowledge creation and we at AVK are happy to assist and offer our advice