Smart Electric Meters over a ZigBee network

Given the awareness about Renewable Energy, Energy Independence, Energy Neutrality and the like – it came as no surprise that when a little remote village in central India decided to get itself some electric power, it considered other options to just getting itself “on the Grid”.

Follows is a brief description of the favoured scenario:

  • Independent electrical network for the village – based on solar energy, biogas, and diesel iotschematicgenerators.
  • This choice of energy was because it was a sun-blessed agrarian village like everywhere in India.
  • Equipment and Operations would be on an Own or Lease model by individual villagers, as opposed to State ownership.
  • The Village Administration (called Panchayat in India) would also like some electrical power for consumption in street lights, community water well pumps, school building and panchayat building electrification, etc.
  • The Panchayat would need to pay the individual power generating individuals for the power supplied.
  • Therefore it is critical that their contribution to the village grid had to be metered and accounted for.


A brief Description of the technical solution:

Let us consider Solar Panels, Biomass tanks and biogas generators, and diesel generators among the power generating equipment installed by the villagers.

Now comes the part that we are interested in.

This equipment is connected to “smart” Moxa meters. Moxa is a company/brand that manufactures these digital meters that can be programmatically interfaced with to retrieve data, and even perform some function. Moxa is a leading provider of industrial networking, computing, and automation solutions.
Digital smart meters can be manufactured to measure any physical flow such as water, gas or electricity. In our case we are interested in the Moxa electric meter. Moxa meters are seen in India used to integrate into complex BMSes(Building Management Systems) for building complexes as part of the strategy for “Green” or “Smart” buildings.

Based on the Moxa meter installation configuration, it would be possible to measure how much power was generated and how much supplied to the Panchayat.
The Moxa meter interface is the Modbus protocol, which is a serial communications protocol.
Since the village was pretty remote, the next question was how data from these individual meters would be collected centrally.
That is when the “IoT” thinking got invoked to suggest a solution since digital devices and independent communication was involved
That is when Zigbee was considered.

We all know ZigBee as the IEEE specification for a suite of communication protocols used to create personal area networks with small, low-power digital radios.
It is simpler and less expensive than other protocols such as Bluetooth or Wi-Fi. It is ideal for short-range low-rate wireless data transfer. ZigBee devices can transmit data over longer distances by using a mesh network of intermediate devices to reach more distant ones.

The smart digital Moxa meters, or their data, could easily be Zigbee enabled.

A suitable Zigbee network configuration with Zigbee enabled meters (installed onsite at individual villagers’ premises) as end devices and Zigbee co-ordinators, could easily address the issue.
An interesting feature of Zigbee devices with regards to its own power consumption is that it “wakes up” only when requested for data by the network, thus enabling a very small power footprint.

In Conclusion
Drill down details for components in this configuration will be made available in future posts. This should be of interest to IoT enthusiasts.

References:
www.moxa.com

https://en.wikipedia.org/wiki/ZigBee

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