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DEE-23216 Introduction to Smart Grids and Renewable Energy — P. Järventausta & S. Valkealahti
Exam 19.10.2017

 

You can answer in English or in Finnish

1. Are the following statements true?

You have three options to be selected: Y = yes, N = no and DK = don't know. Right answer
means one point and wrong answer one minus point. If you choose the option DK (don't know),
you will get zero point. Maximum is 6 point and minimum O point in all.

a) Demand response means shifting the loads from peak times to off-peak periods in order to
flatten the shape of load curve, while energy efficiency means lower energy use to provide
the same level of service.

b) Relay protection practices are simpler and power losses are higher in meshed (i.e. ring)
configuration of power grid than in radial configuration.

c) A microgrid can be determined as a segment of Smart Grid with intended island operation
capability.

d) Global investments in fossil energy based power generation were bigger than in renewable
energy based power generation in 2015.

e) Intergovernmental panel on climatic change has estimated that CO> content in the
atmosphere will be 4 to 5 times higher than at the moment, if all known fossil energy
resources will be used during the next 200 years.

f) New discoveries of oil have been smaller than oil consumption during the last 30 years.

2. a) Compare briefly the roles of electricity retailer and DSO (3p)

b) List the main drivers and barriers for electrification of road transportation (3p)

3. Explain briefly (you can use also a drawing)
a) The day-ahead (spot) electricity market (3p)

b) The reclose seguence of MV feeder protection relay for temporary and permanent faults (3p)

4. a) What is the forecasted cost of energy for electricity produced with wind, solar and
hydropower with respect to coal and nuclear energy based production in 2030. (3p)

b) A hydropower plant has a height difference h between the water levels on both sides of the
dam and an ideal penstock (n = 1) with a cross-sectional area 4. Derive eguation for the
velocity of water in the penstock and for the power of the hydropower plant as a function of /.

(3P)

5. Explain briefly
a) The guantity air mass number (3p)

b) Present technology development trends in wind power (3p)