Detroit Water and Sewerage Department uses UtiliNet radios to implement an AMR/SCADA system

The Detroit Water and Sewerage Department (DWSD) made the decision to implement a Landis+Gyr UtiliNet spread-spectrum radio network to implement both an automated meter reading (AMR) system and SCADA system for each customer community as well as to multiple locations within the city utility.

The problem
The Detroit Water & Sewerage Department (DWSD), Detroit, Michigan, made a major decision in 1998 to automate wholesale water metering operations. Automatically collecting data from its approximately 85 wholesale water customer accounts (which include multiple connections totaling 278 metering facilities, each containing up to four meters) has brought significant billing and operational efficiencies to DWSD. It has also provided for better customer service by giving its wholesale customers ready access to accurate, on-demand meter data. With its water and wastewater system reaching out in a 75-mile radius from its operations centers in Detroit, DWSD provides water and wastewater services to more than 4 million people in seven counties (soon to be eight) in southeastern Michigan. This includes many wholesale community customers.

The solution
Improving efficiency and safety

DWSD officials realized that upgrading its wholesale metering systems, incorporating new communications technologies, and adding new information technology would significantly improve efficiency as well as provide a reliable solution to existing problems. Numerous benefits resulted from this project, including:

• Wholesale customers are provided with on-demand metering data so that customer community personnel no longer have to enter meter pits (OSHA confined spaces) to read meters for verifying DWSD data.
• DWSD personnel also no longer have to travel to and enter the meter pits to read meters.
• Disputes over bills have been eliminated because DWSD and customer communities have ready access to the same flow of data at the same time.
• High rates of flow are reported immediately, thereby more readily aiding in early detection and remediation of water main breaks.
• Consumption is no longer a surprise for a community at the end of each month when the bill arrives, because it has access to real-time meter readings at all times.
• A continuous read system allows for demand billing. DWSD is able to gather data to support a future rate structure based on demand, similar to electrical power companies.

Although the business case for automated meter reading (AMR) impelled DWSD to move forward in identifying and developing its AMR system, several conventional solutions for establishing the system architecture were quickly ruled out because of logistical, technical, and cost concerns. DWSD and Westin Engineers, the city utility’s engineering consultant, then identified a spread-spectrum radio technology, the Landis+Gyr UtiliNet, that provided the solution. In addition, the cost for each metering site was about the same as a CSU/DSU for the phone line, but without the recurring monthly charges.

Enhanced SCADA
Although the project has been driven by its automated metering aspect, there are multiple, overlapping supervisory control and data acquisition (SCADA) projects also in the works. The UtiliNet system allows DWSD to not only connect wirelessly to remote controllers and end devices, but UtiliNet radios also are programmed to interact with microprocessor-based controllers. As a result, command and control functions are undertaken within predetermined parameters, without the requirement of personal attention from the operations centers. Continuous monitoring of pressures and flow data along the system was considered an early priority in the overall automation plan. For example, while the same meter pits are sending average flow data to DWSD’s billing personnel, real-time flow and pressure data is sent to pumping stations for backup control of those stations.

There are also 37 strategic pressures that are continuously monitored within the system in addition to meter pressure at the 278 sites, plus each meter pit will be continuously monitored for flooding, intrusion, and power failures. Regulating valves typically located next to the metering pits are also continuously monitored through the wireless system.

The results
Even with equipment and engineering costs for the new system, the benefit-to-cost ratio and economic value-added study based on a 1997 pilot test provided a positive business case to proceed with the project. DWSD estimated that, compared to using digital phone lines, the payback for the UtiliNet radio system was less than two years.

Other positive aspects of the project include enhanced billing capabilities. “A continuous read system permits prompt correction of problems, and the ability to make frequent reads permits us to go to a demand-based billing system in the future,” says Dennis L. Green, head engineer of water systems. “Increased customer satisfaction results from automation,” says Green. “Automation helps DWSD serve customers’ needs and provide customers with accurate, on-demand water consumption information and instant notification of high rates of flow, which aids detection.”

Automated reading of the city utility’s wholesale water meters was completed at the end of 2000. The addition of 37 wholesale wastewater metering locations will be added in the near future and a network of up to 200 sewer monitors that will share the UtiliNet backbone is currently under design.