Innovation in the service of humanity. Pritpal Singh Professor and Chairman ECE Dept., Villanova University and Percy “Butch” Shadwell Head of Reliable

Innovation in the service of humanity.

Pritpal Singh Professor and Chairman

ECE Dept., Villanova University

and Percy “Butch” ShadwellHead of Reliable Electricity Working Group,

IEEE Humanitarian Technology Challenge

(with contributions from Syed Jafri)

Presentation to IEEE PES July 27, 2010


Team• IEEEPercy (“Butch”) ShadwellRichard BaseilSyed Jafri

• Villanova UniversityNeeta Khare (Postdoc)Renee Daniel (Master’s candidate)

• L3 Communications and Drexel UniversityDavid Williams (Master’s candidate)






Scope Definition

Power Distribution Intelligence

Circuit Protection HMI

Signal Monitoring Code Compliance

Connectors Documentation

Expandability

Modularity

Troubleshooting



Applicable Code

• NEC 2008

• Article 690 for PV installations

• Article 705 for Interconnected Sources

• Article 720 for Circuits < 50V

• UL Standard 1703



Design Considerations

• Terminations

• Cable Ampacity

• Insulation Type

• Module Connectors

• Module Connection Access

• Splices

• Conductor Color Coding



Design Considerations …. cont’d

• Ground Fault– Detection– GF Current interruption– Array disconnect/inverter shut down– GF Indication

• Grounding & Grounded conductors• Branch Circuit• Point of connection



Design Considerations …. cont’d

• Disconnecting means

• Panelboards and junction boxes

• GFCIs and Switches

• System Labeling



Associated Hazards

• A single 6V, 220 Ah storage battery can discharge about 8000A into a terminal-terminal short circuit

• 12V to 600V system present shock hazard

• Listed equipment – UL, CSA, ETL


Project Specifications

• Design for a community center, medical clinic or individual dwelling.

• Stand-Alone Hybrid Power System to provide power for fans, lighting, water pumping, refrigeration, radio, and cell phone charging.

• 24VDC bus selected to minimize wire size and cost.• Initial design is over-instrumented to provide field study

feedback – later implementation designs will be simpler.



Project Design



System Block Diagram



System Components• 2 series-connected 125Wp solar panels

• 2 series connected 75Ah SLA batteries

• Sunsaver MPPT Charge Controller

• Bicycle backup generator

• PIC 24J Microprocessor

• Current and voltage sensing circuits

• Load disconnect circuit

• Circuit protection design

• Fault LEDs



Controller design



Circuit design (sample)

Circuit protection

Current sensor

Connector placement sensor/Fault LED driver

Load disconnect device



Controller Printed Circuit Board

Component side

Solder Side



Project Status• Circuit design….completet• Printed circuit board fabrication…complete• Solar panels, charge controller and battery

acquisition…complete• Programming….almost complete• Bill of Materials… almost complete• Chassis design….in process• Site selection….in process• Testing….not yet started



Next Steps

• Order components and populate boards

• Finalize chassis design and build

• Test control boards

• Settle on test site

• Assemble and test complete system in lab

• Transfer prototype 1st generation systems to test site and monitor performance


Documents

Innovation in the service of humanity. Pritpal Singh Professor and Chairman ECE Dept., Villanova University and Percy “Butch” Shadwell Head of Reliable