California’s Glendale Water and Power Department (GWP) has a nearly century-long history of supplying power and water to its citizens. Serving over 93,000 electric and 34,000 water customers, the utility emphasizes high reliability and embraces new technologies – especially for grid modernization and customer satisfaction.
In recent years, updates to GWP’s grid and communications systems have been a top priority, with increased urban growth driving the need for increased connectivity to more remote locations.
Growing pains
In October 2009, GWP became one of the few public power utilities to receive a U.S. Department of Energy Smart Grid Investment Grant. With this grant, GWP installed smart water and electric meters across the network to modernize its power and water systems. The utility also added water leak detection, electrical sensors, and reclosers to support Distribution Automation (DA). After modernizing the GWP grid using Tropos broadband mesh routers, the network quickly and consistently sent large volumes of data across the GWP grid, delivering end-point performance of up to 15 MB/sec.
Over the past decade, urban population and economic growth, changes in foliage, technological advances, and increased data use combined to create even greater demand for grid reliability, increased capacity, and reduced latency. A larger population meant more remote end-point locations. These remote end-point locations required multiple hops from GWP’s Operations Center, adding congestion to the network. GWP’s operators recognized that the communications system needed to be upgraded as part of grid modernization.
A new hybrid approach
GWP needed a comprehensive, cost-effective solution to account for increased throughput requirements, vegetation growth, and urban development.
GWP sought advice from its vendors. Suggestions ranged from upgrading the metering system and adding more LTE gateways, but the performance of this upgrade was 750 KB/sec to 1 MB/second or selectively adding hybrid LTE routers in areas where communication performance was inadequate. After a detailed analysis, GWP partnered with Hitachi Energy to implement a hybrid solution to resolve operational communication challenges at the optimal cost/benefit.
Hybrid mesh integration
Hitachi Energy leveraged hybrid Tropos/LTE routers to add gateway backhaul locations where fiber was not cost-effective or in areas needing upgraded communication throughput. The solution met the physical challenges of steep terrain, heavy vegetation and new multi-story buildings.
The collaboration between Hitachi Energy and GWP led to the development of a Hybrid LTE design using GWP’s existing broadband mesh and leveraging the LTE capabilities of Hitachi Energy’s TRO620 router to add remote backhaul gateways. The remote gateways could then add increased capacity, performance, and resiliency.
The current mesh deployment includes 382 routers to connect the following:
● 170 Advanced Metering Infrastructure (AMI) devices covering backhaul, meter readings, and disconnection/reconnection.
● 6 devices for capacitor banks
● 32 devices for reclosers
● 45 devices for the PLC used to monitor and control water tank pumps
GWP conducted initial testing for LTE connectivity from remote locations used as backhaul gateways. By adding two TRO620 Hybrid Tropos/LTE routers, encrypted data was passed through an IPsec tunnel over non-private infrastructure, creating a ‘virtual fiber cable’ between the two routers.
GWP placed one TRO620 router at the lower-performing network edge before connecting it to GWP’s broadband mesh network. The second TRO620 unit was installed at a substation, leveraging existing fiber cable to create a virtual connection to the Glendale Wide Area Network (WAN). These changes significantly improved Glendale’s network connectivity performance to over 5 MB/second in the low-performing locations.