|Array Structure||Tracker: Dual Axis|
Concentrated photovoltaic array, Solfocus.
Concentrated photovoltaic (CPV) technologies focus large areas of sunlight onto small, high performance solar cells, maximising output and minimising cost.
CPV technology makes use of very high efficiency, ‘triple junction’ photovoltaic cells originally developed for the space industry. These cells produce large amounts of power at high temperatures and can withstand very high levels of sunlight. The Solfocus CPV array consists of 560 mirror units, each of which focuses 650 cm2 of sunlight onto a 1 cm2 cell and converts sunlight to electricity at a high 24% overall efficiency. By making use of concentrated sunlight, less of the expensive solar cells are used.
Only direct sunlight can be focused by the mirrors in CPV arrays, so tracking systems are used to keep them pointing towards the sun. CPV arrays operate best in clear, sunny conditions, making them most suitable for desert environments.
The first large implementation of this technology in the Southern Hemisphere is installed at the Alice Springs Airport.
Ingenero develops large scale solar energy installations powered by SolFocus CPV. Ingenero is a Queensland based solar company with experience in large scale solar power generation and the provision of various solar solutions around Australia.
|Number Of Panels||2 x 560|
|Array Area||2 x 42.08 m²|
|Type Of Tracker||Solfocus SF-1100S, dual axis|
|Inverter Size / Type||2 x 11 kW, SMA SMC 11000TL-10|
|Installation Completed||Mon, 8 Nov 2010|
|Array Tilt/Azimuth||Variable. Dual axis tracking.|
Notes on the Data
System Disconnection for Cabling Works
All arrays at the Solar Centre were disconnected from approximately 2.00pm to 3.00pm on Monday, 9 July 2018 in preparation for the cable between the main switchboard and distribution board being upgraded. Array sites #23-38 remained disconnected while the main feeder cable to these sites was replaced in subsequent days, but all systems were re-connected by early afternoon on Thursday, 12 July 2018.
Site 22: Brief Tracking/Generating Interruption
The SolFocus CPV tracking arrays (site #22) experienced minor disruptions on 27-28 February 2018. While one tracker continued to generate energy, its tracker functions were intentionally disrupted for maintenance and investigation purposes. The other array, at a similar time, ceased generation for a short duration due to its inverter voltage threshold settings, which have now been reset. The operation of both arrays is now restored.
Solfocus Trackers - Back On line
Both Solfocus trackers are fully operational again. Replacement motor control board was installed in one unit and the other unit recalibrated and tracking correctly again.
Monitoring Interruption for UPS Battery Replacement
The disconnection and re-connection of the solar arrays and weather station equipment while a new site connection was being established prompted the already flattening UPS batteries which power the site’s energy meters to fail and require immediate replacement. Data recording was affected from approximately 2.30pm ACST, Monday 10 July to 4.00pm, Wednesday 12 July.
Affects weather data for DKASC, Alice Springs
Site 22: Tracker Operational
One of the two Solfocus trackers went offline ~21st April 2016. The cause was traced to a faulty motor drive board. This was replaced today and the CPV system is now once again in full operation.
Site 22: Inverter Fault
One of the two inverters on these arrays has developed an intermittent fault and shutdowns for several hours most days at around midday. This issue is being investigated and when a solution is found a notification shall be made.
System Outage - Sites 4, 5, 17, 20, 22, 34 and 35
On the 5th June 2015, A Friday before a long weekend, seven individual PV systems at the DKASC were switched off by unknown persons and for unknown reasons. The outage was not noted until the following Tuesday when O&M staff returned to work and found the main circuit breakers for sites 4, 5, 17, 20, 22, 34 & 35. turned off. These systems were all turned back on again on the 9th March when the problem was detected.
Site 22: Inverter Failure
An inverter failure occurred resulting in the loss of all output from one of the two Solfocus trackers. On investigation the inverter was found to have had a loose phase connection which resulted in arcing and eventually burnt out the input terminals to the inverter. The loose phase connection would have been due to a poor installation technique. The inverter was returned to SMA and replacement provided and installed. The replacement was installed in earlky May 2015.
Site 22: Solfocus Issue
The Solfocus Concentrated Photovoltaics system data was taken offline for 1 week for rectification work due to it’s lower than expected output. The technology supplier identified that this issue is not due to the failure of the tracking system, but rather the dynamics of the interface between the grid and inverters. The supplier carried out rectification work.
> Answer to Spotlight Question
Onsite at the DKA Solar Centre in Alice Springs are a series of quiz-like Spotlight Questions at each array. Visit the centre and scan the QR code at each sign to test your knowledge – and check your answer here!
Q: What other technologies use concentrating solar effects to direct sunlight at a point?
A: Concentrating solar-thermal power plants use a field (or rows) of curved mirrors to focus sunlight onto a central receiving point, which heats a fluid that can store energy for future electricity generation or heating; this is known as CST or CSP technology. A similar principle is also applied on a much smaller scale in outdoor solar cookers. Concentrating solar photovoltaic systems (CPV technology) can also use mirrors but in an individual configuration of parabolic mirrors that direct the sunlight onto a small photovoltaic cell to generate electricity. Many optical devices also focus light, channelling it through a lens to magnify objects - or, in the case of naughty little brothers, burn innocent bugs with a magnifying glass!