Integration of Superconducting coil with a Shunt Active Power Filter for Power
Quality Improvement in a Power Distribution System
T. Penthia, A.K. Panda and S.K. Sarangi
Dept. of Electrical Engg., NIT Rourkela, India
=
+
𝑣𝑏1
∗
𝑖𝑠𝑏
=
∗ =
𝑖𝑠𝑐
∆+
1
+
𝑣𝑐1
∆+
1
1 𝑇
(𝑣 𝑖
𝑇 𝑡1−𝑇 𝑙𝑎 𝑙𝑎
𝑝𝑙𝑎𝑣𝑔 + 𝑝𝑙𝑜𝑠𝑠
(1)
𝑝𝑙𝑎𝑣𝑔 =
𝑝𝑙𝑎𝑣𝑔 + 𝑝𝑙𝑜𝑠𝑠
(2)
𝑝𝑙𝑜𝑠𝑠 = 𝑘𝑝 ∆𝐸𝑠𝑚𝑒𝑠 + 𝑘𝑖 ∆𝐸𝑠𝑚𝑒𝑠 𝑑𝑡
𝑝𝑙𝑎𝑣𝑔 + 𝑝𝑙𝑜𝑠𝑠
(3)
50
L
0
20
0
i
-20
s
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0.65
Time (second)
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Time (second)
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cb
i
s
20
(A)
i (A)
0
-50
0.5
Zs
isa
ila
b-ph
isb
ilb
c-ph
isc
ilc
Non-linear
Load
0.5
(A)
(V)
cc
dc
20
i
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Time (second)
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Time (second)
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SMES
(A)
100
50
i
(V)
s
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Time (second)
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1
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1
6
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Time (second)
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5
0.8
(kW)
0.55
E
SMES
790
(V)
PCC
400
200
0
-200
-400
0.5
-50
0.5
dc
 The instantaneous symmetrical component theory (ISCT) control technique is used in the PCS of
the SMES device to perform the compensation process efficiently.
0.8
780
4
3
2
1
V
 This presentation deals with integration of Superconducting coil with a Shunt Active Power
Filter (SAPF), termed as SMES system, for Power Quality Improvement .
0.75
50
 Harmonics not only increases the losses in the system but also produces unwanted disturbance
to the communication network, voltage, current stress, etc.
 This has motivated the introduction of an SMES based SAPF for improving the power quality.
0.7
-20
Fig. 3: Simulation results for the SAPF
s
 In addition to the problems of unbalance and reactive power loading, the power system
distribution network is also facing challenges because of harmonic loading in the system.
0.65
Time (second)
V
770
0.5
V
 Some traditional methods of generating reference currents and the sources of power quality
problems are reviewed.
0.6
780
i (A)
integration of renewable energy sources, system line faults, etc. are the main cause of power
quality issues.
0.55
0
790
 Non-linear loads (namely adjustable speed drives (ASDs), arc furnaces, switched mode power
supply (SMPS), uninterruptible power supply (UPS) systems, semi-conductor devices etc.),
Source
(5)
50
 Today, power quality problems are the main challenging issues in a power distribution system
due to the integration of renewable energy sources into the grid and huge utilization of
semiconductor devices.
a- ph
(4)
SIMULATION RESULTS
-50
0.5
INTRODUCTION
+ 𝑣𝑙𝑏 𝑖𝑙𝑏 + 𝑣𝑙𝑐 𝑖𝑙𝑐 ) 𝑑𝑡
+
+
+
Where 𝑣𝑎1
, 𝑣𝑏1
and 𝑣𝑐1
are the fundamental positive sequence voltages at the respective
+ 2
+ 2
+ 2
phase load terminal and ∆1+ = 𝑣𝑎1
+ 𝑣𝑏1
+ 𝑣𝑐1
.
i = i (A)
This paper mainly focused on a novel power conditioning system (PCS) for a superconducting
magnetic energy storage (SMES) device in a power distribution system for power quality
improvement. PCS of the SMES device involves a voltage source inverter (VSI) based shunt active
power filter (SAPF), and a superconducting coil is coupled with the SAPF through a bi-directional
chopper. The system is associated with harmonics in the supply current, voltage distortion and
unwanted reactive power due to a three phase non-linear load fed by a three-phase AC mains. In
this paper, the SMES device is investigated for line voltage regulation, harmonics reduction, power
factor correction and reactive power compensation in the power system. The instantaneous
symmetrical component theory (ISCT) control technique is used in the PCS of SMES device to
perform the compensation process efficiently. The superconducting coil is intended to regulate the
DC link voltage of the VSI-SAPF very quickly so that the total power loss in the VSI can be
minimized. Simulation activities of the proposed system have been carried out in a
MATLAB/Simulink environment to check its effectiveness over conventional SAPF.
+
𝑣𝑎1
∆+
1
(A)
ABSTRACT
∗
𝑖𝑠𝑎
ca
Poster ID: 10-P3-251
770
0.5
0.55
0.6
0.65
Time (second)
0.7
0.75
0.8
0
0
0.5
0.6
Time (second)
Fig. 4: Simulation results for the SMES
 From the results, it has been observed that the DC-link voltage of the SAPF is quite fluctuating in
nature causes more switching losses and conduction losses in its VSI. But in the case of SMES device,
the DC-link voltage almost constant, indicates effective compensation, less power loss in VSI and
stability of the system.
 THD of the source current and input power factor of the system is found better using the SMES
device than that of SAPF, illustrated in table-1.
 However, SMES device has some drawbacks like, it has high initial investment cost and needs high
maintenance than the SAPF.
Table-1: Performance parameters of the system:
Three phase IGBT
based inverter
DC/DC
Superconducting
Convereter
coil
With Compensator
Vdc Cdc
Zc
VSI
Switching signals
HBC
∆Vdc
vs
vl
il
Switching signals
ISCT Control
Technique
Ploss
Esmes(ref.)
PI
Fig.1: Proposed SMES system coupled with source and load
CONTROL STRATEGY
+
PI Controller
Ploss
isa
*
i
il
vl
vs
Moving
Average Filter
sa
Plavg
Extraction of
+
+
+
(v
,v
,v
a1
b1
c1 )
fundamental +ve
sequence
components
Generation of
reference
source currents
www.PosterPresentations.com
+
i
-
isb
*
sb
+
-
isc
*
i
sc
Fig. 2: Block diagram of the ISCT control technique
RESEARCH POSTER PRESENTATION DESIGN © 2012
324.10 V, 8.76%
45.15 A, 19.83%
45.15 A, 19.84%
0.91
With SMES
324.86 V, 5.19%
48.74 A, 4.10%
47.12 A, 19.89%
0.946
325.21 V, 2.45%
46.87 A, 1.96%
45.91 A, 19.85%
0.995
REFERENCES
Esmes
Esmes(ref) -
PCC voltage , THD
Source current , THD
Load current , THD
Input Power Factor
With SAPF
A comparison has been made between the SAPF and SMES system for power quality improvement
in an electrical power system.
THD of the source current for the SMES system is observed 1.96%, thereby satisfying the IEEE-5191992 standard on the harmonic limits.
The DC-link voltage of the SMES system is almost constant i.e. ripple free whereas the dc-link
voltage of the SAPF is not free from ripples.
Hence, from the simulation results of both SAPF and SMES system, it has been noticed that the
performance of the SMES system is far better than the SAPF for the power quality improvement in
a power system.
Esmes
isa isb isc
Vdc
Without Compensator
CONCLUSION
∆Esmes
Vdc(ref.)
Performance parameters
+
-
HCC1
ig2
ig1
HCC2
ig4
ig3
HCC3
ig6
ig5
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