Part 1

Wind energy (20% of total coursework mark)

Take the last three letters of your student number to produce a value between 000 and 999. Add 100 to this value and multiply the result by 100. This is the nominal power rating, in watts, measured at a wind speed of 15 m/s of the wind generator model you are to use.

Assuming an overall efficiency of 35%, calculate the theoretical blade diameter of your wind generator. Use the air density value stated in Energy Model 1.

Use ‘Energy Model 1’ to observe the theoretical characteristics of your wind generator. Produce a graph of power output against wind speed, limiting the output power to its nominal rating

Visit the site ‘www.weatherunderground.com’. Choose any location on Earth positioned at least 30° of longitude and 20° of latitude from your family home and observe the forecasted wind speed data for the next 10 days. Consult with your colleagues to ensure that you have not selected a town that is the same as any other member of the cohort. This location is also to be used in Part 2c and Part 3 of this assignment.

Enter the wind speed forecast data into ‘Energy Model 1’ to enable a prediction to be made of the energy your wind generator is expected to produce over the next 10 days. To simulate this in a sensible time, make each Simulink step equal to 10 minutes (simulation time of 1440). The energy integration calculations will need to be modified accordingly.

Document your work clearly, stating your observations and discussing your results.

Part 2

Solar energy (20% of total coursework mark)

This part of the coursework uses the following spreadsheets, which are available on Course Resources:

Solar Spreadsheet Daily:  ‘NOAA_JSR_Daily_MarkeatonSt_Derby_180_37_21Mar17’

Solar Spreadsheet Annual:  ‘NOAA_JSR_Annual_Guesthouse_Tanzania_33_75’,

Instruction on the use of these spreadsheet will be provided during lecture and tutorial sessions.

Use of these spreadsheets is limited to this coursework only.

a.     Determine, using Google Earth or other means, the latitude and longitude of your family home. Use the Solar Spreadsheet Daily to determine the path of the sun at that location on the four solstice and equinox dates of the year 2018 – 20 March, 21 June, 23 September and

21 December. Show these using the ‘Elevation vs azimuth’ and ‘Elevation vs time’ graphs (8 graphs in total). Comment on your results.

b.     Define the orientation of three panels as follows:

Panel A: Suitable for general use all year – azimuth of due South or North and tilt set to give a reasonable level of solar irradiation all year.

Panel B: Positioned for improved morning irradiation. Set this for maximum irradiation at 9am on the date of the March equinox.

Panel C: Positioned for improved afternoon irradiation. Set this for maximum irradiation at 3pm on the date of the March equinox.

Use the Solar Spreadsheet Daily to determine the ‘Solar irradiation of a panel as a proportion of maximum irradiation’ for panels A, B and C on 20 March, 21 June and 21 December (9 graphs in total). Comment on your results.

c.     Your mission is to investigate the operation of a solar panel array at the location you selected in Part 1 of this assignment.

      The panels to be used are based on Mitsubishi Electric Photovoltaic Modules series 255Wp.   

      The specification sheet can be found here:

                https://www.mitsubishielectricsolar.com/images/uploads/documents/specs/MLU_spec_sheet_250W_255W.pdf

Use the ‘Solar Spreadsheet Annual’ spreadsheet, modifying the input values to meet your requirements. The efficiency value to be entered into the spreadsheet is given in the specification sheet as ‘Module efficiency’.

             The total area of your array is determined as follows:

i.              Use the last two digits of your student number to create a number between 00 and 99.

ii.             Add 50 to that number. iii. The resulting number is the area of your solar photovoltaic array in units of m².

Define an orientation for the array that will produce a reasonable spread of daily energy throughout the year and investigate the operation of your array. Comment on your results.

Experiment with a range of panel orientations and comment on your findings. 

Document your work clearly, stating your observations and discussing your results.

Part 3 

Integrated energy management (20% of total coursework mark)

The wind generator you modelled in Part 1 and the solar array you modelled in Part 2 are to be used in an integrated energy management system for a real application.

See Energy model 3. This integrates the wind energy supply model to a load demand.

Develop a model for an integrated energy management system to include your wind generator and solar array, to be located near the town you have chosen.

Include in your model a realistic demand scenario that utilises some 75% of the energy generated at the times of the Spring and Autumn equinox (22 March, 22 September).

Run your model over a 10 day period and note the results.

Run your model for the times of the year around the Summer solstice and the Winter solstice and note the results.

Comment extensively on your model and your results. Suggest ways in which your model could be modified to better reflect a practical energy installation.

Part 4 

Investigation of MATLAB/Simulink power electronics models (20% of total coursework mark)

A number of MATLAB/Simulink power electronics example simulation circuits are available to you on Course Resources.

This part of the coursework is an investigation of the characteristics of at least one of these models.

This is an open ended exercise. You are encouraged to investigate in any way appropriate the operation and characteristics of the models.

As an example, the Simulink inverter models could be investigated by studying the effects of:

Changes of sinusoidal reference frequency and amplitude

Changes to the PWM switching frequency

Effects of using PWM frequency not a multiple of the signal (sinusoidal) frequency

Effects of changes to filter cut-off frequency

Effects of introducing higher pole filters

Effect on signal of changes to load including introducing inductive load

Using additional Simulink measurement blocks to investigate levels of third harmonic distortion (THD) Difference between half wave and full wave bridge driving circuits

Document your observations and critically evaluate your findings in a way that demonstrates your understanding of the circuits.

Part 5 

Case study (20% of total coursework mark)

A hospital located in Tanzania is connected to the country’s electrical power grid (Tanesco) but experiences power outages often and for a very variable length of time. The hospital must have a reliable and continuous power supply in order to function effectively and for patient safety. A system is to be developed to enable power to be available for the use of the hospital during power outages in the grid supply.

Tanzania has a grid supply of frequency 50Hz, 380V ph-ph or 220V single phase. It is known that the hospital has an average load to the grid of 100kVA and a peak load of 135kVA. More detail than that is not known at this stage, so the specification that follows is based on assumptions that may not be correct for this particular site.

A power supply is to be available to the hospital at all times.

In the event of power failure from Tanesco, the peak total load demand of 135kVA 3-phase is to be supplied by a diesel generator. It is intended that this generator is not to be left running during periods of normal supply but will be started when the supply fails.

A diesel generator of 50kVA 3-phase is to be available to supply emergency services and the two critical areas below should the main generator fail to operate when required.

Two critical areas require high integrity uninterruptable supplies. The three operating theatres require an uninterruptable 3-phase supply of peak 10kVA and average 4kVA for a period of up to 10 minutes and the computer centre requires an uninterruptable single phase supply of peak 3kVA and average 0.5kVA for a period of up to 30 minutes. The switching over of the sources of supplies to these critical areas should be uninterrupted and should not involve voltage spikes of greater that 10% of supply voltage.

An HF SSB communications transceiver with a maximum transmit power output of 100W is to be made available for emergency use and should be able to be  operated from a separate battery supply rated to provide an average power of 25W for 2 weeks.

A UK charity has negotiated a loan from a UK bank for the purchase of the capital equipment for the project at a fixed annual discount rate of 4.25% to be repaid monthly over 20 years. Equipment can be sourced from any country but all transactions should be made in £GB.

Your task is to specify and source the equipment required for the project and to present an outline of the system in the form of a block diagram and a clear list of the equipment to be used as well as sufficient information to allow the equipment to be purchased from a supplier. As a minimum, this should include, but not be limited to, all those parts shown in bold above. You should cost the equipment and calculate the total capital cost of it and the monthly repayments that will need to be made by the hospital to the bank.