Deck 22: Commercial Utility Interactive Photovoltaic Systems

Question 1

Using the and module frame grounding location specified in the module installation instructions is the only way to ensure connection integrityfor the life of the system.

A)ground-fault current
B)aluminum frames
C)combiner boxes
D)grounding hardware

Answer 1

D

Question 2

The NEC requires all utility interactive inverters to be listed to UL 1741.Please explain the two key requirements of the standard.

Answer 2

The NEC requires all utility-interactive inverters to be listed to UL 1741.PV system designers and installers should be aware of two key requirements of the standard.The first is known as anti- islanding.Utility-interactive inverters are required to automatically turn off when utility power is lost.This prevents an inverter from feeding electricity back into the utility electrical grid, which would be extremely dangerous for utility workers.Remember that the 240 volts produced by an inverter can produce 12,000 volts or more on the primary side of utility transformers if the inverter were allowed to back-feed the utility system.In effect, the utility transformer would be operating
as a step-up transformer.Another important requirement of UL 1741 is for dc ground-fault protection (GFP).Ground faults in PV source circuits (array) do not result in the high fault currents produced by utility electrical services.Photovoltaic modules are a current-limited source.Short- circuit current from a module is slightly higher than normal module output to the inverter, but not enough to open an overcurrent device (fuse or circuit breaker).Ground-fault current will flow through bonded exposed metallic structures and raceways to the inverter and then back to the source (modules).

Question 3

Grounded conductors, whether dc or ac, must be identified with white or insulation in accordance with NEC 200.6.

A)orange
B)gray
C)green
D)black

Answer 3

B

Question 4

How can the photovoltaic effect can be put to practical use in a commercial building?

Question 5

Commercial utility interactive PV system may require a designer to specify the supply-side connection permitted by NEC 705.12(A).

A)size
B)height
C)weight
D)width

Question 6

Ampacity correction for temperature must be considered for both the dc and ac system conductors.

A)ambient
B)minimum
C)maximum
D)below normal

Question 7

A -line diagram is an electrical schematic diagram for the utility interactive PV system.

A)single
B)double
C)split
D)reduced

Question 8

The most common material used today for production of photovoltaic cells is .

A)crystalline silicon
B)magnesium phosphate
C)synthetic silicon
D)potassium chloride

Question 9

What has the 2011 NEC required for arc-fault protection, and what are its three functions?

Question 10

What is a single-line diagram, what is its purpose, and what information should it include?

Question 11

A ground-mounted photovoltaic module array for a commercial building may be constructed so that it can be used as ____.

A)a storage area
B)a covered walkway
C)covered vehicle parking
D)a break area for building occupants

Question 12

The general procedure for inverter startup is to check and current levels from the source (modules) to inverter closing disconnects as needed to accomplish this.

A)ampacity
B)wattage
C)voltage
D)conduction potential

Question 13

The equipment that converts the direct current produced by modules into an alternating current (ac) output is known as a(n) ____.

A)reverter
B)converter
C)inverter
D)diverter

Question 14

modules are the basic building block of a utility interactive photovoltaic system.

A)Semiconductor
B)Photovoltaic
C)Solar
D)Aluminum

Question 15

The installation of utility interactive solar photovoltaic systems has accelerated in recent years due to energy conservation and concerns.

A)environmental
B)electrical
C)solar
D)semiconductor

Question 16

The maximum dc source current is defined by NEC 690.8(A) as the sum of parallel module rated short circuit currents multiplied by percent.

A)110
B)125
C)150
D)200

Question 17

A(n) is simply a collection of modules that form a complete photovoltaic generating unit.

A)generation
B)combiner
C)modulation
D)array

Question 18

Describe the requirement for a grounding electrode system for a utility interactive photovoltaic installation.

Question 19

The plans for commercial PV projects usually have to be submitted to the for review and comment prior to issuance of a permit.

A)AHJ
B)CFP
C)PVJ
D)BHO

Question 20

NEC 705.10 requires that a(n) that indicates all interconnected power sources for the premises be installed at the service and the location(s) of the power production source(s).

A)removable label
B)sign
C)instruction sheet
D)permanent plaque or directory