ABSTRACT:
Electric Spring is an emerging smart grid technology,
which can provide voltage support to weakly regulated system. This paper
studies the effect of load variation on the performance of electric springs.
Two different single phase circuits with intermittent power supply have been
simulated for the study – with one electric spring and with two electric
springs. The loads considered are linear and are identical. Results obtained in
MATLAB/Simulink environment show that line voltage is regulated by electric
spring irrespective of variation in load. A brief comparative study is done
between the simulation results obtained from the two circuits to observe the
effect of the additional electric spring. This study tests the effectiveness of
electric springs in a circuit designed to be more realistic, i.e., when the
loads are not ON all the time and multiple electric springs are distributed all
over the grid.
KEYWORDS:
1.
Demand Side Management
2.
Electric Spring
3.
Renewable Energy Sources
SOFTWARE: MATLAB/SIMULINK
Fig.
1. Schematic Diagram of Electric Spring connected with Intermittent Renewable
Energy Source
BLOCK DIAGRAM:
Fig.
2. Block Diagram for Circuit with Two Electric Springs
EXPECTED SIMULATION RESULTS:
Fig.
3. RMS Voltage for Boosting action in single ES circuit
Fig.
4. Active and Reactive power consumption of ES during Boosting action in single
ES circuit
Fig.
5. RMS Voltage for Reduction action in single ES circuit
Fig.
6. Active and Reactive power consumption of ES during Reduction action in
single ES circuit
Fig.
7. RMS Voltage for Boosting action in double ES circuit
Fig.
8. Active and Reactive power consumption of ES during Boosting action in double
ES circuit
Fig.
9. RMS Voltage for Reduction action in double ES circuit
Fig.
10. Active and Reactive power consumption of ES during Reduction action in
double ES circuit
CONCLUSION:
This
paper demonstrates the effects of load variation on the performance of ES. From
the simulation results, it can be noted that, for boosting mode of operation,
the ES can regulate the line voltage at the reference value irrespective of
variation in load. However, for reduction mode of operation, the load variation
causes fluctuations in the line voltage even when the ES is operating. This
might be improved by making the circuit more inductive, which will assist the
ES for reduction action. The basic single ES circuit was modified by adding an
extra ES to it. It was observed that the reactive power consumption of each ES
decreased by almost 50% for both modes of operation. Therefore we can conclude
that as the number of ES in the circuit increases by a factor of ‘n’, the
reactive power consumed by each ES to carry out the same magnitude of
regulation decreases by a factor of ‘n’. This decreases the stress on each ES
as well as the inverter rating for ES. For this study, the linear and identical
loads have been considered, which can be further extended to non-linear and non-identical
loads. Also, the random load profile can be replaced with a real time load
profile.
REFERENCES:
[1] IEA, World Energy Outlook 2015: IEA. Available:
http://www.worldenergyoutlook.org/media/weowebsite/2015/WEO2015 _Factsheets.pdf
[2] P. P. Varaiya, F. F. Wu and J. W. Bialek, "Smart
Operation of Smart Grid: Risk-Limiting Dispatch," in Proceedings of the
IEEE, vol. 99, no. 1, pp. 40-57, Jan. 2011.
[3] D. Westermann and A. John, "Demand Matching Wind Power Generation
With Wide-Area Measurement and Demand-Side Management," in IEEE
Transactions on Energy Conversion, vol. 22, no. 1, pp. 145-149, March 2007.
[4] P. Palensky and D. Dietrich, "Demand Side Management:
Demand Response, Intelligent Energy Systems, and Smart Loads," in IEEE Transactions
on Industrial Informatics, vol. 7, no. 3, pp. 381-388, Aug. 2011.
[5] A. Mohsenian-Rad, V. W. S. Wong, J. Jatskevich, R. Schober,
and A. Leon-Garcia, “Autonomous demand-side management based on gametheoretic
energy consumption scheduling for the future smart grid,” IEEE Trans. Smart
Grid, vol. 1, no. 3, pp. 320–331, Dec. 2010.
