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Reduce Streetlamp Power Consumption

Hafslund is Norway’s largest supplier of electric power and security, managing streetlights for local councils throughout the country. Recent government legislation required that all streetlamps containing polychlorinated biphenyls (PCBs) had to be replaced by January 2007. This legislation presented the ideal opportunity to upgrade the streetlamp control systems. With this in mind, a new
intelligent, energy-conscious project was started to find a way to monitor and control streetlamps remotely.

Reducing Consumption
A state-of-the-art monitoring and control system requires reliable and cost-effective communication. GPRS was the best solution for communications based on coverage, cost and installation flexibility. Hafslund’s goal was to reduce the considerable amount of power consumed by lighting roadways, as well as to increase the lifespan of the bulbs to lower maintenance costs.
More than 100 Digi TransPort GPRS cellular routers communicate with 80 to 100 streetlamps each through an intelligent concentrator head end unit that is connected directly to the power lines from which each lamp feeds. The GPRS network is built using a private APN provided by Telenor Mobil, Norway’s leading mobile operator. The router’s role is to provide reliable and cost-effective communication between the server and the concentrator head end. The Digi TransPort router sends detailed information about power consumption, bulb life expectancy and failure via its GPRS facility back to Hafslund’s head office.

Street Lighting When It’s Needed

To maximize efficiency, streetlamps have been programmed to reduce their output at times when less intense lighting will still provide a good level of visibility. The system achieves this by constantly comparing the input it receives with a pre-programmed scenario and sending alarms via the GPRS.

Intelligent Street Lighting and Billing

The system also has the option to network with motion sensors that actively detect when there is no traffic and consequently no requirement for normal lighting levels. In this instance, the system signals the head end unit (which controls power levels) to reduce power levels on the appropriate lamps. This in turn instantly reduces the levels of lighting to conserve energy. Similarly, as soon as the motion sensor detects traffic again, a signal is sent to increase the lighting level.

The system’s ability to distinguish between individual bulbs on a network (and their individual power consumptions) enables Hafslund to bill multiple end users from the same power line. For example, if a private business adjacent to one of Hafslund’s power lines wants to provide lighting in their car park but from the same lamppost, the system would enable power consumption for each use to be measurable and billed individually.

Future Street Lighting Projects

As an energy conservation and cost savings exercise, this project has shown a 62-64% reduction in power consumption. The Digi TransPort GPRS routers provide reliable communications compared to conventional systems that just need to turn lamps on/off. Hafslund plans to apply this winning formula on a larger scale.
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Remote cellular access to streetlamps reduced power consumption by 62-64%.


Application: Telemetry

Industry: Electricity provider

Company: Hafslund

Challenge: Hafslund needed to upgrade their streetlamp control system for remote monitoring and control in order to reduce power consumption, increase lightbulb lifespan and reduce costs.

Solution: Digi TransPort GPRS routers communicate through an intelligent concentrator head end unit and server to deliver detailed information back to Hafslund’s head office.

More About Digi TransPort
The Digi TransPort family of upgradeable cellular routers provides secure high speed wireless connectivity to remote sites and devices. The routers can be used for primary wireless broadband network connectivity or backup to existing landline communications. They stand apart from the competition with true advanced
routing, firewall and security features including stateful firewall inspection and integrated VPN.

    Key Features:
  • Reliable and cost effective
  • Easy to deploy
  • Integrated VPN
  • Digi Remote Manager software for large installations
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