Solar Energy TechnologySolar Energy TechnologyScience Summer CampScience Summer Camp

Session 9: Fri 9:00 AM - 12:00 N : Field trip to Energy Masters and

Installing/Commissioning the System

Day 3 Introduction Day 3 Introduction

• Description of Facilities – if needed

• Go Over Day 2 and rest of Course

• Handout Notes

• Review Safety Rules Safety Rules

– Safety first– Always follow safety rules

Session 9 TopicsSession 9 Topics

• Installing the System (Instructor TBD)– Utility Interconnection– Permitting and Inspection. Details of Role

Inverters

• Commissioning, Maintenance, and Troubleshooting

• Activities:

33

Getting Up and Running, Maintenance and Trouble shooting• Utility Interconnection

• * Permitting and Inspection. Details of Role Inverters

• * Commissioning, Maintenance, and Troubleshooting

• * Activities:

PV System Design and Installation

LO 10 Performance Analysis and Troubleshooting

Task/Skill

10.1. Describe typical system design errors

10.2. Describe typical system performance problems

10.3. Associate performance problems with typical causes

10.4. List equipment needed for typical system performance analysis

10.5. Compare actual system power output to expected

10.6. Identify typical locations for electrical/mechanical failure

Performance Analysis and Troubleshooting(7% of test questions)

Overall PV System Efficiencies

PV Array Input (DC) = 70 to 80%

AC Output (AC)

Reference 2

Typical Design Errors

General Issues

1. Not accounting for shading issues (trees, chimneys, inter-row spacing, etc.)

2. Inadequate structural support (wind, snow, seismic and dead loads)

Inverter Issues

1. Under/oversizing PV array relative to inverter capacity

2. Too many modules in a string (Voc x Temp Correction < Max Inverter DC input)

3. Too few modules in strings (Vmp with temp correction to make sure that do not drop below inverter cut-off voltage)

4. Under sizing wires for voltage drop (see voltage drop formula)

NEC Issues

1. Under sizing overcurrent protection devices (Isc - fuses and circuit breakers)

2. Under sizing wires for ampacity requirements (Isc – wire sizes, conduit fill and temperature correction factors, etc.)

3. Equipment labeling

Performance Analysis and Trouble Shooting Tools

1. Basic tool kit (screw drivers, etc)

2. Irradiance meter

3. Multimeters

DC Voltage

DC Current (Clamp-on / Hall Effect)

AC voltage (RMS)

AC current (RMS)

4. Hydrometer (battery systems)

PV System Problems from 1000 Solar Roof Project in Germany

Reference 2

Check Site Conditions

1. Module Condition

2. Array Condition

3. Roof condition

4. Array Shading

5. Inverter Condition (error messages, signs of charring, unusual noises, hot spots)

6. Wiring (connections, insulation abrasion, discoloration)

Check Performance

Inverter Efficiency = Displayed AC Power

Array Imp x Array Vmp

Array IV Curve

1. Take irradiance temperature and measurement.

2. Apply correction factors3. Measure Isc (current) and Voc (voltage)

being produced by the array4. Compare theoretical to practical

Check for Ground Faults

1. Possible signs

2. Voltage-to-ground from PV module frames, rack, inverter and other equipment.

3. Blown Ground Fault Fuse (> 1 amp fault)

4. Error code (minor fault)

5. Isolate and test individual module strings

Causes

Reference 3

1. Loose, broken or pinched wires

2. Loose connections

3. Rodent damage

Current Paths

Ground Fault Protection

Normal Operation

Current Paths

Positive Ground Fault

Current Paths

Negative Ground Fault