MSc A ssignment2021
Renewable Energy Systems Integration (RE S I)
Instru ctions
Marks: 50% of the module total marks.
Due date and time: on Friday 26th March 2021 at 2 pm
Each student is required to submit an individual and formal report. The problem has no unique
approach/ solution and therefore the methods/ solutions are expected to be varying from one student to
another.
Students may make best possible assumptions if any extra information is required, however, they
should be justified in a Micro Grid context, giving relevant reasons with appropriate references.
Submission will be via Canvas, please familiarise yourself with Canvas before submissions are due.
Files are to be smaller than 20MB to be able to submit to the Canvas.
Maximum number of pages in your report, excluding the cover page, must not be more than 15
(Including appendices). Minimum font size of the body of the report should be 11. Font size of the
captions of figures and tables must be 10. The file type must be PDF.
Late submissions will be penalised by deducting 5% marks per day late. Assignments will not be
accepted more than 20 days late after the submission deadline.
A cademic Integrity
Plagiarism will not be tolerated. It is the act of a Student claiming as their own, intentionally or by
omission, work which was not done by that Student. Plagiarism also includes a Student deliberately
claiming to have done work submitted by the Student for assessment which was never undertaken by
that Student, including self-plagiarism and the other breaches. Sanctions of a plagiarism include the
Student failing the Programme of study.
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P roblem S tatement
Figure 1 shows a schematic diagram of a micro-grid model. The micro-grid must supply its own
electricity demand using Wind, PV, and diesel power generation. Suitable energy storage technologies
including electric vehicles and/ or batteries can be used to support any energy shortage in the microgrid
system. Diesel power generating units are also available to provide standing reserve in the events
of any significant need of the micro grid system. The micro-grid should be designed in such a way that
it facilitates the grid connected and islanded modes of operation while respecting the economic
stability, security, and efficiency of micro grid system.
One of the design objectives of the micro-grid is to use renewable power generation at most of
the operating conditions and then to use minimum level of fossil fuelled power generation. However,
the energy and energy supply security of the micro grid should not be compromised with the maximum
use of renewable power generation, unless otherwise micro grid loads are flexible. The micro grid
design should also consider potential electricity demand growth at 10th and 20thyear time horizons.
You should find typical demand growth at 10- and 20-year cycles through the publishes articles/
reports at a particular location.
The micro-grid has six load centres which are represented as buses 3, 4, 5, 6, 7 and 8. The
technical data of the electricity demands of consumers are given in Table 1. It is given that 50%, 60%,
and 80% of loads respectively connected at buses 4, 5, and 7 are critical loads. A number of fixed speed
wind turbine units are installed at buses 3, 5 and 8 to supply the local demand in conjunction with
diesel units. Diesel units can be installed as a central generation by locating at a single bus or dispersed
generation by locating units at distributed buses. Each wind turbine unit is rated at 66 kW and a number
of units can be connected to a bus as per the technical specification of the micro grid system. The wind
turbine units should be installed considering the technical and economic benefits of the micro grid. The
loads connected at buses 6 and 8 represent residential and commercial loads and it is also proposed to
install a number of 5 kW rated PV modules at these buses to supply 40% of the active power load
demand at Bus 6 and 8.
Table 2 shows the feeder technical data which can be used to determine the sizes of feeders
that are suitable for the micro-grid. Micro-grid feeders are to be designed to carry at least 120% of
excess loading from the peak loading at any operating condition at any time. Table 3 gives the average
loads of each bus in a sample day considering the daily average of the corresponding month,
normalised wind power output, and peak sun hours in the sample day. Wind power output is
normalised by dividing the actual power output of the wind plant by its installed capacity. The diesel
units can be selected from a pool of n1 #30 kW , n2 #60 kW , n3 #150 kW , and n4 #250 kW , where
1 2 3 4 n , n , n , and n represent any number of diesel generators that are suitable for the micro grid
specification.
(1)Describe the design and operating strategies that you would implement to the micro grid to benefit
micro grid system owner and operator considering climate change and global warming effects and
technical and economic perspectives. Note that the remaining parts of the assignment should be driven
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through your proposed strategy in this part considering the given specifications of the assignment and
any extra thoughts adopted to further develop the specification considering a realistic busines case.
[10]
(2)Draw a complete schematic diagram showing the detailed component connections of wind, PV,
diesel, and others that are needed to operate the micro-grid system smoothly in real-time by expanding/
extending Figure 1. Also describe how each component/system in the expanded/ extended micro grid
system operates considering operating functions of each key element of the micro grid system.
[10]
(3)
Calculate the number of (a) wind turbine units and (b) PV modules required to meet the demand of the
micro-grid as per the given specification in the assignment and the design & operating strategies
proposed in part (1).
(c) Determine the number of diesel units, their sizes, and their locations in the micro-grid.
(d) Size the micro grid feeders using the given technical and costing data to meet the loading and other
conditions of the proposal.
(e) Use energy storage solutions as needed and size them justifying technical and economic benefits.
(f) Size capacitor banks for the micro grid system to compensate for reactive power demands at loads.
Consider the efficiency of a PV system as 64%. Assume that there are no shading effects.
Also, consider that the power losses of a feeder can be approximated to 2.5% of the electricity demand
through the respective feeder. Show all the calculation details, assumptions, and technical and
economical justifications as appropriate.
[60]
(4)Present a formal report covering (1) to (3) sections, presenting the engineering judgements you
made, a discussion, conclusion, and references. The arguments, discussions, and conclusions must be
made by referring to the given case of the assignment. No marks will be given if a student just
reproduces conclusions, discussions, or justifications that are commonly available in published
literature or textbooks. [20]
Students are allowed make reasonable and realistic assumptions; however, they should be technically
feasible and economically justified. Students may use online (or published) technical data apart from
the data given in the assignment; however, the sources of information should be given as references.
The marker will only mark what is in the body of the report and not the contents in the appendices.
Long tables of data such as Excel tables should be placed in appendices.
Table 1: Load data
Bus number Peak load (MVA) Power factor
3 0.55 0.82
4 0.82 0.88
5 1.24 0.85
6 0.44 0.87
7 0.61 0.86
8 0.46 0.88
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Table 2: Feeder technical data
Given
identifications of
feeder sizes
R (Ω /km) X (Ω /km) Capacity (kVA) Price
(£/MVA/km)
S1 0.25 0.13 120 152,000
S2 0.18 0.13 140 152,000
S3 0.13 0.1 160 152,000
S4 0.07 0.1 230 152,000
S5 0.05 0.1 300 152,000
Table 3: load demand and generation data
Sample day Demand at each load bus
in % of peak connected
load
Normalised output of
wind power generation
Peak sun hours in the
sample day
1 92 0.36 4.22
2 96 0.32 3.33
3 85 0.38 3.32
4 88 0.22 5.38
5 95 0.34 4.54
6 98 0.28 5.85
7 100 0.30 5.88
8 95 0.32 5.80
9 90 0.32 3.86
10 92 0.36 3.24
11 90 0.34 4.42
12 95 0.33 2.12
3-ph, 0.55 MVA
PF = 0.82
3-ph, 0.82 MVA
PF = 0.88
3 2 4
1 Utility grid connection
l=0.62 km l=0.94 km
3-ph, 12.0 MVA, 11 kV/415 V
l=1.0 km
1-ph, 0.44 MVA
PF = 0.87
3-ph, 0.61 MVA
PF = 0.86
6 7
3ph, 1.24 MVA
PF = 0.85
5
1-ph,0.46 MVA
PF = 0.88
Micro Grid
l=0.35 km 8
Figure 1: l = length of the feeder, PF = power factor, an arrow indicates electricity demands of
consumers