Meeting - October 18 2018

30 members and guests attended our AGM and enjoyed two good presentations over dinner at the Auburn Hotel, Hawthorn.

Electrical engineer Peter Hart spoke on solar panels. 

Peter covered how inverters work; how much energy is available and how much can be captured;  technical standards and the CEC, the accreditation of installers, feed-in tariffs.  Problems were outlined, and they are significant - inverter failures, isolation switch failures and panel shorting to ground.  Limits to achievable energy outputs were outlined, and an explanation of how the Tesla Powerwall and its Gateway work.  His summary points were -

• A solar panel installation is complex electrical equipment. It needs to be checked regularly.
  
• Inverters and batteries should be installed in the shade.
  
• The DC isolator problem (failures common) has not been solved.
  
• Roof-mounted DC isolators need to be in the shade.
  
• The grid excessive voltage problem is unsolved.
  
• Community battery storage / microgrids are needed in high solar uptake areas.
  
• The predicted output energy from domestic solar units should be discounted because it is the domain of amateurs.
  

Engineer Richard Lightfoot next presented three case histories on interlocking system failures - all illustrating an evident failure by the designers to think through what users might actually do - thus, where to put the relevant sensor, when a second sensor was advisable, etc.