Tuesday, January 26, 2010

WISA and IEEE Joint Meeting

Program: Solar Power Technology

Speakers and Topics:  
     Bill Balascio, P.E., Carew Associate, Inc.: 
     Power & Monitoring Design Basics for Solar PV

     Balascio discussed three PV installations: two used PV arrays; one also had passive solar.

     Design Basics:

  • Site evaluation
  • Funding and evaluation
  • Design trade-offs

     Ray Greenhalgh & Ryan Marlborough, United Electric Supply: 
     Solar PV System Design & Output Considerations
     Talk given by Mike Howell. 

     System performance depends on:

  • Location Insulation
  • Weather
  • Temperature; as temp rises, voltage goes down
  • Array direction, especially tilt relative to the ground.
  • Shade usually if some of the cells are shaded, the inverter has problems trying to find best voltage
  • System components
    > Inverter
    > Solar module
       * Crystalline runs at 14% efficiency, runs better when weather cooler 
       * Thin film runs at 8-9% efficiency, runs better when warmer 
       * Power tolerance
       * Panel mismatch 
       * Light induced degradation; crystalline can degrade 3%, thin film by 10-15 %.
       * Soiling
       * Age
  • How the Array matched to the inverter(s).

     Scott Bowden, Solectria Renewables, LLC: 
     Applications of Solar Grid-Tie Inverters
     Talk given by Sid Shu

     The company started out looking at electric cars.
     Inverter reliability is a result of good transformers.
     Ruggedness
     Simple to maintain
     94% efficient
     Types of inverter systems:
       > Micro -- high frequency, used for less than 500 watts
       > String of inverters 20 kHz or less, used for less than 10 kw
       > Central 12 kHz or less, used for 10kw to 1MVA
     Anti-islanding (the PV may continue to power when the surrounding grid is down by using a turn-on/turn-off sequence)