2. Introduction To Microgrid
What is Microgrid?
Small-Scale Power Supply Network to
provide Power for a Small Community.
Local Power Generation for local loads.
Small Power Generating sources
Highly Flexible
Efficient.
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3. Contd..
What is Microgrid?
It is connected to both the local generating
units and the utility grid thus preventing power
outages.
Excess power can be sold to the utility grid.
Size of the Microgrid may range from housing
estate to municipal regions.
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4. The Need Of Microgrid
Microgrid could be the answer to our energy
crisis.
Transmission losses gets highly reduced.
Microgrid results in substantial savings and
cuts emissions without major changes to
lifestyles.
Provide high quality and reliable energy
supply to critical loads
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5. Microgrid components
wind turbine
Microturbine
Photovoltaic system
Controller
Fuel cell
Energy storage system
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6.
7. Wind turbine
Wind pushes the fan blades of wind turbine and
produce energy output.
No control over the energy output.
Microturbine
microturbine are single staged combustion
turbine.
Usually powered by biogas, natural gas,
propane.
8. Photovoltaic system
PV cell is a self-contained electricity producing
device consist of semiconducting material.
Light striking on the semiconducting material in
PV cell, creating dc.
Fuel cell
FC uses an electrochemical process to turn
hydrogen and oxygen to electricity.
9. Energy storage system
ESS include electrochemical battery, super
capacitor, compressed air energy storage, super
conducting energy storage, flywheel energy
storage etc. .
Lithium ion is commonly used because best
energy to weight ratio and slow loss of charge
when not in use.
ESS store energy at the time of surplus and
redispatch it when needed.
10. Contd..
ESS plays an important role in microgrid.
Sizing of ESS to be considered first when
considering ESS in MG.
ESS increase the reliability of power system.
The cost of ESS includes one time ESS cost and
the annual maintenance cost.
The battery storage system made up of small
battery blocks.
12. Microgrid Operating Modes
Island Mode:
Utility grid is not supplying power
Static switch is open.
Feeder A, B, C are being supplied
by Microsources.
Feeder D (not sensitive )
is dead.
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13. Microgrid Operating Modes
Grid Connected Mode:
Utility grid is active.
Static switch is closed
All the feeders are being
supplied by utility grid.
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14. ESS in islanded microgrid
Sizing of a suitable battery bank in terms of
power and energy help in shaving the peak
demand.
Stores excess renewable energy and supply
load when renewable energy is low.
When ESS discharges its energy to power grid
its generating positive real power
15. ESS in grid connected microgrid
The upstream grid can be treated as
bidirectional generator which generate positive
power when power is transferred from the MG
and generate negative power when the power
transferred from the MG to upstream grid.
The output of bidirectional generator is limited by
the capacity of transmission line between the
MG and upstream grid.
17. Algorithm steps
1.Enter forecasting renewable power and load.
Calculate minimum BESS capacity CEmin.
2.Set CEmax , ∆ CE and initialize the variables.
3.Solve the objective function for CE. Minimize the
TC for islanded MG and maximize TB for grid
connected MG.
4.If CE < CE max, update CE using the above
equation . The algorithm will stop when
CE ≥ CEmax.
18. Conclusion
BESS for MG decrease the schedule cost of MG
in islanded MG and increase benefit of MG.
As the size of BESS increases, the benefit
increases.
The TCPD increases in a constant rate and
when the size of BESS is greater than optimal
size TC will increase in islanded MG and TB will
reduce in grid connected MG.
19. REFERENCES
[1] Microgrid Energy Management Framework Jul. 2009
[2] H. T. Le and T. Q. Nguyen, “Sizing energy storage
systems for wind power firming: An analytical approach
and a cost-benefit analysis,” in Proc. Power Energy Soc.
Gen. Meet., 2008
[3] S. Chen and H. Gooi, “Scheduling of energy storage
in a grid-connected pv/battery system via simplorer,” in
Proc. TENCON IEEE Region 10 Conf., Nov. 2009
