Testing Methods Flashcards

The Performance Ratio (PR) of a PV system is best described as which of the following?

Answer: Actual energy yield divided by the reference yield based on irradiance and rated power

PR compares actual output with theoretical output at the measured irradiance, so it can be compared across weather conditions.

Which standard defines the methodology for capacity testing of PV systems in the U.S.?

Answer: ASTM E2848

ASTM E2848 provides a regression-based method for reporting PV system capacity at reporting conditions.

A ground fault in a PV array is suspected. Which measurement best helps locate the fault position within a string?

Answer: Measuring voltage from each string conductor to ground and comparing the ratio

The ratio of positive-to-ground and negative-to-ground voltages indicates roughly which module in the string is faulted.

What does a polarity test at commissioning confirm?

Answer: String positive and negative conductors are correctly identified and connected

Polarity verification prevents reverse connection of strings, which can damage inverters or combiner components.

Continuity testing of equipment grounding/protective earthing conductors in a PV array is performed to verify what?

Answer: A low-resistance bonding path between frames, racking, and the grounding system

Continuity testing confirms that exposed metal parts are effectively bonded so fault current can safely clear.

When comparing measured string short-circuit current (Isc) with expected values, the measurement must be normalized mainly to what?

Answer: Plane-of-array irradiance

Isc is nearly proportional to irradiance, so it must be scaled to measured POA irradiance before being compared.

Which inverter test verifies that the unit stops energizing the grid when utility power is lost?

Answer: Anti-islanding test per IEEE 1547.1/UL 1741

Anti-islanding tests per IEEE 1547.1 and UL 1741 confirm the inverter ceases to energize within the required time after a grid outage.