REP Solar Energy Systems 4

Question 1

Which type of solar concentrating technology uses a parabolic dish to focus sunlight onto a Stirling engine at the focal point?

Accepted Answer

Dish-Stirling system

Answer

Dish-Stirling systems use a parabolic dish concentrator to focus sunlight onto a Stirling heat engine mounted at the focal point for electricity generation.

Question 2

What is the main advantage of a microinverter over a string inverter in a residential PV installation?

Accepted Answer

Module-level MPPT that reduces shading and mismatch losses

Answer

Microinverters perform MPPT at each individual panel, so shading or soiling on one panel does not significantly reduce the output of other panels.

Question 3

In NEC Article 690, what is the significance of the 'maximum system voltage' rating for PV equipment?

Accepted Answer

Equipment must be rated for voltages at or above the highest voltage that can appear in the system under any conditions

Answer

NEC 690 requires that all PV system components be rated for the maximum system voltage, which includes the open-circuit voltage corrected for the lowest expected temperature.

Question 4

A 10 kW PV system produces 14,000 kWh annually at a site with 1,750 peak sun hours per year. What is the system's capacity factor?

Accepted Answer

16%

Answer

Capacity factor = actual output ÷ (rated capacity × 8,760 h) = 14,000 ÷ (10 × 8,760) ≈ 16%.

Question 5

What is the primary purpose of grounding the DC negative conductor in a transformerless PV inverter system?

Accepted Answer

Prevent potential-induced degradation (PID) in the modules

Answer

Grounding the negative rail in a transformerless system reduces the potential difference between the module frame and cells, mitigating potential-induced degradation.

(REP) Certified Renewable Energy Professional Practice Test

(REP) Certified Renewable Energy Professional Practice Test

REP Solar Energy Systems 4