Renewable Energy

Question 1

What are four basic configurations that may be used when designing a renewable energy system

Answer 1

1 stand alone off grid
2 utility interactive without batteries
3 utility interactive with batteries
4 hybrid off grid

Question 2

What does the energy source Supply in a stand-alone off grid system?

Answer 2

A charge controller which supplies batteries which Supply DC current to the inverter.

Charge ctrl -> battery bank -> inverter -> ac distribution

Question 3

Which type of system is used has a backup system to supply critical loads in the event the grid is not available?

Answer 3

Utility interactive with batteries

Question 4

What is the purpose of operating the inverter in parallel with the grid for a utility interactive without batteries system?

Answer 4

So that either power supply can provide energy to the load

And if the power source has more power output than the local demand the excess power is sent to the grid

Question 5

What are the two classifications of hybrid systems?

Answer 5

A DC bus hybrid system

An AC bus hybrid system

Question 6

What do the blades of a wind turbine rotate at for wind speeds of 40 to 56 kilometres per hour

Answer 6

14 RPM which gives them a speed of 169 kilometres per hour at the tip

Question 7

What is annular generator technology?

Answer 7

The use of multiple variable low-speed synchronous generators that use Salient poles

The rotor Hub is directly connected to the generator rotor in a wind turbine which eliminates the gearbox and couplings

Question 8

What is the end result of annular generator technology?

Answer 8

Reduced mechanical losses
Elimination of wear and tear of the gearbox
Elimination of oil leakage

Question 9

Describe the three types of inverters referred to in the Canadian electrical code

Answer 9

Combination inverter power conditioning unit
- inverts at a fixed voltage and frequency in a stand-alone system OR following an imposed waveform in an interactive system

Power conditioning unit
- Alters or regulates the output of a power source

Interactive inverter
- used in parallel with an electric utility to ensure the Renewable Energy System output is fully synchronized with utility power

Question 10

What is special about grid compatible inverters?

Answer 10

Equipped with anti-islanding protection which automatically disconnect the inverter from the grid in case of loss of grid power.

Question 11

How can utility interactive inverters be classified?

Answer 11

As
String inverters
Central inverters
Utility-scale inverters
Multimode inverters
Module-level inverters or micro inverters

Question 12

What are the classifications of utility interactive inverters based on?

Answer 12

The size range and primary application