Remote cellular pressure monitoring system gives utility greater confidence

By Chris Polk

Most water utilities monitor their physical plants – tanks, pump stations, treatment plants, etc. – but there is much more data that can be captured in a distribution system. Unless they use remote cellular pressure sensors, water personnel have to travel to sites to manually gather pressure information with gauges or other short time span recording devices. This methodology not only takes valuable time, but only provides a snapshot of what is occurring in the system.

Initially, one water utility, with close to 800 km of water mains, 26,000 metered connections and 26 full-time employees, wanted to record water pressures without having to visit locations routinely to check these using static water pressure gauges on hydrants and faucets.

“Our plan was to install two Mueller Hydro-Guard® remote pressure monitoring sensors as a trial. One sensor was strategically placed to monitor a specific area’s pressure; the second was placed in one of our pressure zones to see what data it would actually provide us,” said Jeff Elrod, water distribution manager.

One advantage of the sensors is that they can be installed anywhere. The first sensor was installed directly into the water main, using a corporation stop fitting in an area where they did not have a vacant meter setter. The second sensor was installed in a high priority area that conveniently had a vacant customer connection available.

Flow tests were then performed in areas monitored by the sensors to simulate different levels of water loss due to a variety of water main break scenarios. The recordings during these simulations were studied to determine when a text alert from the sensors was sent to management. Then, the severity of the issue could be determined based on the pressure drop.

Weekly analysis was performed to study the regular pressure fluctuations during the 24-hour daily use pattern to determine normal and abnormal fluctuations. After testing and review of the normal pressures in the selected distribution areas, high and low alert points were set to allow the sensors to alert water distribution operators to system anomalies that needed to be reviewed.

The utility’s new sensors have provided alerts, notifying personnel of water pressure drops in the system that should not occur if the system is operating as planned. These pressure drops coincide with major water usage and/or loss.

“Several times, alerts received by the sensors have allowed us to put employees in the field to find leaks and turn off water, prior to customers notifying us,” said Elrod. This advance notice can save large volumes of treated water by getting staff on the scene to stop a water main break as soon as it is detected, and potentially saving further property damage in cases where the leak is in the pavement.

There is always the possibility of catastrophic water loss such as a large water main break at night that would go unnoticed by the public, or a SCADA low water tank level alarm failure that is supposed to notify the utility in ample time. In these scenarios, thousands of litres of water have already been lost. A pressure sensor alarm alerting personnel of a significant pressure drop allows emergency crews to address the problem.

“I was pleasantly surprised with all the analytics that were captured, even within the first month of monitoring. We used this information to plan for system maintenance for an issue we could see developing. Without this data we would have waited for a system event for the issue to be dealt with.” said Elrod.

The sensors can be scheduled to upload data to a website multiple times a day and will automatically upload data when an issue is detected. They are a great way to monitor system components such as pressure reducing valves that regulate pressure zones or district metered areas.

“In systems where pressures are greatly influenced by mechanisms such as pressure reducing valves, I see a critical need for a remote method to monitor downstream water pressures better than what we have,” said Elrod.

There are other sensor technologies found in traditional SCADA systems that also have these capabilities, but some small utilities still have limited SCADA implementations. Even those utilities fortunate

to have better capabilities, often have areas where a SCADA sensor is not feasible due to a lack of power, communication lines, or terrain obstacles. Cellular technology bridges the gap to monitor water pressures in areas where SCADA monitoring is not possible.

“Having the confidence that we will be aware of major system issues quicker is the most significant benefit. The analytics that are continuously provided are also extremely valuable for planning and maintenance purposes. A proactive water management style is needed for the aging distribution systems of today’s infrastructure, and these types of sensors provide the ability to be more proactive and less reactive,” explained Elrod.

Chris Polk is with Mueller Water Products. For more information, visit www.muellercompany.com/en-ca