ABSTRACT:
This paper proposes “Electric Spring” (ES) based on
Single Phase three-level Cascaded H-Bridge Inverter to achieve effective demand
side management for stabilizing smart grid fed by substantial intermittent
renewable energy sources (RES). Considering the most attractive features of
multilevel inverter (MLI), an effective structure of Electric Spring is proposed
for suppressing voltage fluctuation in power distribution network arising due
to RES and maintaining the critical load voltage. Also, the operation of ES in
capacitive as well as inductive mode is discussed. Further, the paper describes
droop control method for parallel operation of distributed electric spring for
stabilization the power grid. An exclusive dynamic performance of the system
using electric spring has been tested and demonstrated through detailed MATLAB simulation.
KEYWORDS:
1.
Critical load
2.
Cascaded H-Bridge Inverter
3.
Droop control
4.
Electric Spring
5.
MLI
6.
RES
7.
Smart load
SOFTWARE: MATLAB/SIMULINK
SCHEMATIC DIAGRAM:
Fig.
1. Schematic of Electric Spring.
EXPECTED SIMULATION RESULTS:
Fig.
2. Observed RMS value of (a) Source voltage (Vs), (b)
Non–critical voltage (Vnc), (c) Electric spring voltage (Va)
& current (Ia), (d) Critical voltage (Vc)
in capacitive mode.
Fig.
3. Observed Instantaneous value of (a) Source voltage (Vs), (b)
Non–critical voltage (Vnc), (c) Electric spring voltage (Va)
& current (Ia), (d) Critical voltage (Vc)
in capacitive mode.
Fig.
4. Observed RMS value of (a) Source voltage (Vs), (b)
Non–critical voltage (Vnc), (c) Electric spring voltage (Va)
& current (Ia), (d) Critical voltage (Vc)
in inductive mode.
Fig.
5. Observed Instantaneous value of (a) Source voltage (Vs),
(b) Non– critical voltage (Vnc), (c) Electric spring voltage
(Va) & current (Ia), (d) Critical
voltage (Vc) in inductive mode.
Fig.
6. THD analysis of (a) Two-level and (b) Three-level CHMLI based ES.
CONCLUSION:
The
paper proposes new approach for regulating the mains voltage using MLI based ES
for smart grid applications. The implemented Three-level CHMLI based ES for
smart grid application effectively regulates the ac mains voltage and reduces
the THD content as compared with Two-level VSI based ES. The effectiveness of
ES is validated through digital simulation in terms of THD. Lastly simulation
results of droop control for Four Electric springs have been implemented in a large-scale
distributed pattern in order to make multiple ES act in coordinating manner so
as to have robust stabilizing effect.
REFERENCES:
[1]
Edward J.Coster, Johanna M.A.Myrzik, BAS Kruimer, “Integration Issues of
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vol.99, no.1, pp.28-39,
January, 2011.
[2]
Koutsopoulos and L. Tassiulas, “Challenges in demand load control for the smart
grid,” IEEE Netw., vol. 25, no. 5, pp. 16–21, 2011.
[3]
M.H.J.Bollen, “Understanding Power Quality Problems: Voltage Sags and
Interruptions,” IEEE Press, 2000.
[4]
N. Hingorani and L. Gyugyi, Understanding FACTS, Concepts and Technology of
Flexible AC Transmission Systems. New York: IEEE Press, 2000.
[5]
M. Parvania and M. Fotuhi-Firuzabad, “Demand response scheduling by stochastic
SCUC,” IEEE Trans. Smart Grid, vol. 1, no. 1, pp. 89–98, Jun. 2010
