SE Engr. Technical Specifications 5 — Questions and Answers
Question 1: Which standard covers design qualification and type approval (reliability testing) of terrestrial PV modules?
- IEC 61215 (Correct answer)
- IEC 61730
- UL 9540
- IEEE 1547
Correct answer: IEC 61215
IEC 61215 covers performance and durability testing, while IEC/UL 61730 covers module safety.
Question 2: A datasheet lists a mechanical load rating of '5400 Pa front / 2400 Pa rear'. The front rating mainly addresses:
- Wind uplift
- Snow loading (Correct answer)
- Hail impact
- Thermal cycling
Correct answer: Snow loading
Front-side (downward) load represents snow, and rear-side load represents wind uplift.
Question 3: A battery has a nominal capacity of 10 kWh and a rated depth of discharge of 90%. What is its usable capacity?
- 8.0 kWh
- 9.0 kWh (Correct answer)
- 10.0 kWh
- 11.1 kWh
Correct answer: 9.0 kWh
Usable capacity = 10 kWh × 0.90 = 9.0 kWh.
Question 4: What does round-trip efficiency on a battery storage datasheet represent?
- Energy delivered on discharge divided by energy supplied on charge (Correct answer)
- Number of cycles before reaching 80% capacity
- Inverter peak conversion efficiency
- Self-discharge rate per month
Correct answer: Energy delivered on discharge divided by energy supplied on charge
Round-trip efficiency is the share of charging energy recovered on discharge, typically 85-95% for lithium-ion systems.
Question 5: Which standard is the safety listing for complete energy storage systems, with a related test method for thermal runaway fire propagation?
- UL 1703 / UL 1703A
- UL 9540 / UL 9540A (Correct answer)
- UL 1741 / UL 1741 SB
- IEC 62109 / IEC 62109-2
Correct answer: UL 9540 / UL 9540A
UL 9540 lists ESS equipment, and UL 9540A is the test method for thermal runaway fire propagation.
Question 6: A warranty guarantees 98% of power in year 1, then a 0.55%/year decline. What minimum power is guaranteed at the end of year 25?
- 84.8% (Correct answer)
- 86.25%
- 80.0%
- 87.5%
Correct answer: 84.8%
98% - (24 × 0.55%) = 98% - 13.2% = 84.8%.
Question 7: In the IP68 rating of a junction box, what does the first digit '6' indicate?
- Protected against continuous immersion
- Completely dust-tight (Correct answer)
- Protected against water jets
- Rated for 6 kV impulse
Correct answer: Completely dust-tight
The first IP digit covers solids, and 6 means fully dust-tight; the second digit, 8, covers continuous water immersion.
SE Engr. Technical Specifications 5
Which standard covers design qualification and type approval (reliability testing) of terrestrial PV modules?