Past Paper Questions - Jan 2016 (2)

Question 1

In the UK, more than 5GW of PV generation has been added into the network since 2010. Describe some of the problems that could arise for the low voltage network in suburban areas with large numbers of PV installations.

Answer 1

Photovoltaics usually produces most power in the middle of the day, when the domestic demand is at its lowest, so power is exported. This can cause voltage rises and potential voltage limit breaches. There is also potential for reverse power flows, increased power flows and overheating risk in transformers.

Question 2

The UK government has recently committed to build a new nuclear power station at Hinkley Point. Give some of the advantages and disadvantages of nuclear power.

Answer 2

Advantages: Large scale generation, huge quantities of power, baseline requirements met, carbon-free generation, fuel supply from a stable country.

Disadvantages: Expensive, waste disposal, inflexible generation (non-dispatchable) therefore does not compliment renewables

Question 3

Argue whether or not you think building new nuclear stations is in the UK will be an effective approach in achieving a low carbon electricity supply.

Answer 3

It could be argued that new nuclear power stations will achieve a lower carbon electrical supply, however with the huge potential for renewable development in the UK I do not believe this is an effective approach. Investing into renewable energy will prove effective for future generations.

Question 4

The Scottish Government has set a target for the amount of electricity generated annually through renewable sources to equal the gross annual electricity consumption by 2020. Briefly discuss how the electricity network could accommodate this amount of renewable generation.

Answer 4

Achieving the target will require a large renewable capacity (mainly from wind power). During a renewable deficit period, interconnection with the rest of the UK will be required to back up the demand. During renewable surplus, power will be required to be exported to the rest of the Uk.

Question 5

Give two key difference between synchronous and induction generation

Answer 5

1. Rotor speed lags synchronous speed in induction generators whereas synchronous generators the rotor speed matches the synchronous speed.
2. Induction generators always absorb the reactive power, whereas the synchronous generators can be operated to export or absorb reactive power.