Testing Methods Flashcards
7 cards from real SE ENGR. practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Testing Methods flashcards as text
Which standard defines the commissioning tests and documentation requirements for grid-connected PV systems?
Answer: IEC 62446-1
IEC 62446-1 specifies system documentation, commissioning tests, and inspection requirements for grid-connected PV systems.
Standard Test Conditions (STC) for PV modules specify which combination?
Answer: 1000 W/m², 25°C cell temperature, AM1.5
STC is 1000 W/m² irradiance, 25°C cell temperature, and an AM1.5 spectrum.
During an I-V curve trace, a pronounced step or notch in the curve most commonly indicates what?
Answer: Shading or a mismatched/bypassed cell group
Steps in the I-V curve appear when bypass diodes activate because of shading, cracked cells, or mismatch.
A reduced slope near Voc on an I-V curve (a 'tilted' right side) is primarily a symptom of what?
Answer: Increased series resistance
Higher series resistance, such as from corroded connectors or solder bond failures, flattens the curve near Voc and reduces fill factor.
An insulation resistance test on a PV array is typically performed by applying a DC test voltage between which points?
Answer: Shorted array positive/negative conductors and ground
IEC 62446-1 insulation resistance testing applies voltage between the array conductors (often shorted together) and earth.
Which safety precaution is essential before shorting PV string conductors for an insulation resistance test?
Answer: Use a rated shorting switch/device and isolate the string from the inverter
Shorting live DC strings requires a properly rated shorting device with the string isolated to avoid arcing hazards.
When measuring string open-circuit voltage, why is it compared against a temperature-corrected expected value?
Answer: Voc decreases as cell temperature rises
Voc has a negative temperature coefficient, so the measured value must be corrected to be compared fairly with the expected value.