Commissioned by CAT Projects, a remote area energy management specialist, the brief was to address the unique problems facing remote indiginous communities in the Northern Territory.



Background

Unlike urban areas, remote communities face unique challenges, including:

  • Limited access to power.
  • Higher cost of delivery of power.
  • Quota on power consumption.

Our Brief

General design considerations provided in the brief incuded:

  • Must provide reliable radio communications over 100m using an unlicenced band as per AS4268.
  • Must provide Category III over-voltage isolation and safety.
  • Metering system must have an accuracy of +/- 10% worst case.
  • Must have an easy to comprehend display.
  • Must be able to operate in hot, dusty outdoor environments (i.e. must be to IP54 or better rated, be highly UV and heat resistant).
  • Must need appropriate safety and emissions standards.
  • Must support 100V - 240V high efficiency power supply design.

Requirements of the Meter

Specific requirements in relation to the meter were as follows:

  • Must have a USB interface for data download and calibration upload.
  • Must be partially weatherproof, UV resistant and flame retardant.
  • Must be fitted with a back lit display and an external antenna.
  • Must communicate with the display over a low power unlicensed band radio with a range of up to 100m.
  • Radio must remain within Australian AS4268 radio telecommunications radiation limits.

Meter Logic


Requirements of the User Display

Specific requirements in relation to the meter were as follows:

  • Must have 4 digit 7 segment LED display along with a LED dial indicator of instantaneous power usage.
  • Must have LED bar graph of accumulated energy usage.
  • PCB must have an ultrasonic sensor that wakes up the display when motion is sensed in front of the meter.

User Display Logic


Outcomes

We undertook the following systematic development program:

  • Analysis of required standards.
  • Design for manufacture of meter and display hardware.
  • Firmware review and recommendations, and oversight of the third party development.
  • Development of test procedure for meter and display.
  • Certification of meter and display.

  • The result was a fit-for-purpose solution, comprised of a meter and user display unit, that were manufactured and suppled within 3 months.