Page 22 - DECT Today - Issue 3 - May 2015

Testing in the field
In-field testing was a key part of the development and verification of the new Panasonic Industrial Devices SUNX wireless monitoring system. These tests were carried out in conjunction with NTT facilities out at various solar arrays in Japan, including the Onomichi Solar Power Plant near Hiroshima. The plant’s solar array was split into 4 sections each containing 110 strings of around 12 solar modules. Each section had a central data concentrator / DECT base station, and each string had a DECT-enabled monitoring node.
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NEW DECT APPLICATION SEES THE LIGHT OF DAY
New DECT application sees the light of day
DECT-ULE (ultra-low energy) was designed to reduce DECT’s power consumption for use in sensor networks. But the extensions to the DECT standard that DECT-ULE brings can open doors to all kinds of new applications that don’t depend on low energy consumption. That was exactly the case when Dialog and Panasonic Industrial Devices SUNX teamed up to create a brand new DECT application: a wireless monitoring system for solar panels.
Concerns over fossil fuel reserves and carbon emissions have driven the growth of commercial solar power plants. These plants typically have hundreds or even thousands of photovoltaic (PV) modules producing electricity direct from sunlight. Operators looking to deliver predictable power to the grid need to ensure all their modules are working correctly. But with so many modules, how do you notice a single failure? And how do you identify which one module of the thousands has failed?
Cutting costs for solar power plants
Panasonic Industrial Devices SUNX wanted to give solar power plant operators a simple and cost effective way to answer those questions. So they teamed up with fellow ULE Alliance member Dialog Semiconductor to develop a DECT-based wireless monitoring system for solar farms. The system monitors the output from each module – or string of modules connected in series – and sends the results to a central data collation point via DECT. The central unit can be connected to the internet, allowing the operator to monitor the plant remotely.
The system offers plant operators a number of benefits. Firstly, it allows them to immediately spot any failures in the solar array and pinpoint the module or string where the failure has occurred. This allows them to improve the efficiency of their maintenance and repair programs. Moreover, as a wireless system, it can be installed as part of a new plant or retrofitted to existing arrays at lower cost and complexity than a wired solution.
New directions
Solar panels may not be everyone’s first thought for a DECT application, but DECT-ULE is in fact a natural choice for such a system. Originally targeting sensor networks, DECT-ULE has extended the number of Portable Parts (PP) that can connect to one Fixed Part (FP). For example, Dialog’s software allows up to 128 PPs per FP. This is ideal given the large number of modules in a solar plant, allowing operators to cover their entire array with just a few base stations. What’s more, the sleep / wake-up cycle is a natural fit for the periodic monitoring solar modules require.
“The solar power monitoring system shows how the Internet of Things extensions that came from the DECT-ULE technology are opening up new applications for standard DECT. Through this collaboration with Panasonic Industrial Devices SUNX , we’ve taken DECT in a completely new direction,” said Patrick Barels, Principal Applications Engineer at Dialog Semiconductor.
Panasonic developed the monitoring nodes and base stations based on Dialog’s SmartPulse wireless modules and development boards. To
support a high ratio of nodes to base stations, the two companies developed an innovative time-multiplexing approach. This ensures each of the hundred or so monitoring nodes connects to the base station every 10 minutes – without interference or signals crashing.
DECT’s blend of characteristics was the perfect match for the system we wanted to create, and working with Dialog made developing the communications side simpler – so we could focus on the application. Together, we’ve created a system that can help solar power plants control their operating costs and deliver reliable power output to the grid.
After extensive testing (see below), Panasonic launched the monitoring system as a commercial product in December 2014.
DECT Today - The Success Story Continues · www.dect.org