A Group of More Than a Dozen Distribution Cooperatives Across Minnesota are now connected to a private, licensed 700-MHz wireless broadband IP communications network. The system has been deployed across most of Minnesota, the “Land of 10,000 Lakes” (the state's nickname), a 55,000-sq mile (142,449-sq km) service territory. This network supports field automation and will be key to advancing Smart Grid applications.

ADVANCING THE SMART GRID

Since going live in 2006, Great River Energy (GRE; Maple Grove, Minnesota, U.S.), the leader of this initiative, and a growing group of its member distribution cooperatives, including Connexus Energy (Ramsey, Minnesota, U.S.), have already used the standards-based communications network for a wide range of applications, including demand-response and voltage-management programs, distributed-generation dispatch and control, advanced metering communications, substation automation, and T&D supervisory control and data acquisition (SCADA).

Smart Grid prospects are on our industry horizon, and the speed of change can induce a full-blown attack of future shock, a paralyzing fear when confronted by too much change in too short of a time. With this deployment, GRE has laid a communications foundation that effectively short circuits the Smart Grid-related future shock that is hitting much of the utility industry. As new applications and new substations are tied into the network weekly, GRE and its member co-operatives consider ways in which the network can support the future Smart Grid, while helping them work together today to lower costs and improve service.

Connexus Energy has engaged the network in support of distribution substation communications at more than 20 locations with applications for distributed-generation control programs and a voltage-management demand-response program that saves members more than US$250,000 on the hottest days of summer.

PROJECT OVERVIEW

GRE is the fifth-largest generation and transmission co-operative in the United States, with $1.7 billion in assets. Its 28 member cooperatives in Minnesota and Wisconsin distribute electricity to approximately 650,000 homes, businesses and farms. Not only does GRE serve an extensive customer base, but its network also covers more than 60% of Minnesota.

Collectively, GRE's member cooperatives have 100 transmission substations, more than 4500 miles (7242 km) of transmission lines and more than 480 distribution substations. This large, rural territory frequently faces floods, snowstorms and searing summer heat. Therefore, to effectively serve customers across the large service territory, while continuing to build a user network, the communications network needed to be secure, efficient and in real time.

THE BUSINESS CASE

Several years ago, GRE defined requirements for an integrated communications network that could replace its aging telecommunications infrastructure. The previous communications links, implemented over a couple of decades, were usually implemented for individual application purposes, and they were engineered with whatever technology fit best for that particular situation. In addition, GRE faced rapidly increasing demand on its generation resources. Potential solutions needed to address the growing concerns of all utilities for greater operating efficiencies, reliability and security.

In this case, GRE decided that investing in an integrated IP communications infrastructure would most directly meet the long-term needs of the utility and its distribution cooperative members. GRE sought a project that would mitigate its vulnerability to technology obsolescence. While technology innovations come fast and sometimes end abruptly, the ongoing partnership GRE formed with Arcadian Networks (Valhalla, New York, U.S.) as a managed service broadband IP network provider has paid dividends. Arcadian has continued to make ongoing investments in the network since the original deployment started in 2006.

PROJECT RISK MANAGEMENT

GRE faced two major risks in deploying a wireless network: the spectrum license and the radio technology equipment. Through their partnership, GRE and Arcadian Networks established a shared network model, which allows both parties to share the network capability, as well as the cost and risk of deployment and operations. Acting as the “anchor tenant” and network manager, GRE moved to a standards-based converged IP communications network, which allows for use by each of its member cooperatives and enables gradual migration to fit the members' individual communications needs. To date, 15 of the 28 distribution cooperatives GRE serves have deployed, with additional deployments underway. Through its licensed spectrum, Arcadian was able to provide GRE and its members a completely integrated wireless broadband network to accommodate standards-based SCADA applications and a range of additional ensuing applications.

SYSTEM DESIGN

How many towers do I need? What coverage can I expect? Proper and complete answers to such questions would require a detailed radio frequency (RF) study based on specific requirements and the availability of tower and installed fiber assets in the service territory. GRE deployed an integrated long-term solution that incorporates its fiber backbone network across approximately 60 communications sites. These are complemented with endpoint RF network substation sites provisioned with remote access points served by the 700-MHz wireless network coverage from 67 tower sites across the territory. The Network Operations Center at GRE provides firewall-secure service for the network that is controlled and managed by GRE. The Arcadian 24/7 network operations center in New York provides second-level support.