Components & Configurations

Question 1

what are two components to form a PV-direct irrigation system

Answer 1

PV Module; DC water pump

The PV-direct irrigation system only operates when the sun is shining, with power flowing directly from the PV module to the load, in this case a DC pump. A PV-direct system does not provide AC power, so an AC service panel and inverter are not required. Similarly, because there is no energy storage in a PV-direct system, batteries are not needed, and therefore a charge controller is not required.

Question 2

A device that uses electricity to perform a task is a _____________.

Answer 2

load

Any piece of equipment that runs on electricity – lights, welders,
air-conditioners, freezers, computers, and anything else that “plugs in” – is a load.

Question 3

An inverter changes ________ into _______.

Answer 3

DC electricity; AC electricity

An inverter changes DC electricity, from a battery or PV array, into AC electricity. This AC power can then be used by conventional household loads, or, depending on local regulations, be exported to the grid.

Question 4

A piece of equipment that distributes power to branch circuits protected by circuit breakers is called a(n) ________.

Answer 4

electrical service panel

An electrical service panel (or main load center) is used to distribute power to loads through branch circuits that are each protected by a circuit breaker.

Question 5

What are three components to form a grid-direct PV system

Answer 5

Inverter; ac service panel; PV array

A grid-direct system consists of a PV array and at least one inverter, connected to the grid, usually at an AC service panel. Because there is no on-site energy storage, batteries and a charge controller are not required. Grid-direct systems do not power DC loads

Question 6

What is one component that appears in large-scale PV power plant systems and is not usually present in smaller residential PV systems?

Answer 6

step-up transformer

explanation: Step-up transformers are used to change low voltages to higher voltages, and are not typically part of residential PV systems.

Question 7

What are three components to form a DC stand-alone PV system that powers DC loads at night.

Answer 7

batteries; charge controller; pv array

In a DC stand-alone PV system batteries are required to provide power at night. A charge controller is also required to regulate the PV array and ensure it does not overcharge the batteries. Lastly, all DC loads are connected to a DC load center.

Question 8

Which type of PV system would be most appropriate for a railroad crossing in a remote area, approximately 50 miles to the closest utility grid tie-in location?

Answer 8

stand-alone

A stand-alone PV system is ideal for remote applications where the grid is not present.

Question 9

What is this components appropriate function when used as part of a solar PV system: Batteries

Answer 9

stores electricity

Question 10

What is this components appropriate function when used as part of a solar PV system: Inverter

Answer 10

converts electricity from DC to AC

Question 11

What is this components appropriate function when used as part of a solar PV system: Charge Controller

Answer 11

regulates electricity

Question 12

What is this components appropriate function when used as part of a solar PV system: PV module

Answer 12

generates electricity

Question 13

True or False? A PV-direct system is an ideal power source for an emergency lighting system.

Answer 13

False

PV-direct systems only produce electricity when the sun is shining, making them a very poor choice for any load that needs power at night, like a lighting system.

Question 14

In order for a PV system to provide AC power, the system must include a(n)________.

Answer 14

Inverter

An inverter changes DC power from PV modules and/or batteries into AC power for use in homes and businesses. A charge controller regulates DC current from the PV array, but does not convert it into AC. A PV system can produce AC power without a connection to the grid or utility meter, as in an off-grid system

Question 15

True or False? All loads can operate on both AC and DC electricity.

Answer 15

False

Most loads run on either AC or DC; very few are able to use both types of electrical current.

Question 16

True or False? Any inverter with an AC output is a grid-interactive, and can be connected to the utility grid.

Answer 16

False

An interactive inverter must be specifically designed, tested, and listed for interactivity with the utility grid. Furthermore, some interactive inverters work with certain utility grid configurations but not others, depending on the region.

Question 17

True or False? A typical grid-direct system can provide backup power for emergencies and blackouts.

Answer 17

False

A typical grid-direct PV system cannot provide backup power for
emergencies or during blackouts. In most cases, to provide power when the grid goes down, a PV system must include on-site energy storage, usually in the form of batteries (for example a multimode system). A typical grid-direct system has no energy storage. Furthermore, grid-direct systems are required to turn off when the grid fails, for the protection of utility workers who may be repairing equipment on the grid.