ABSTRACT
The flexible ac-transmission system (FACTS) family
called distributed power flow controller (DPFC). The DPFC is derived from the
unified power flow controller (UPFC) with eliminated common dc link. The active
power exchange between the shunt and series converters, which is through the
common dc link in the UPFC, is now through the transmission lines at the third harmonic
frequency. The DPFC is to use multiple small size single phase converters
instead of large size three phase series converter in the UPFC. The large
number of series converters provides redundancy, thereby increasing the system
reliability. As the D-FACTS converters are single phase and floating with
respect to the ground, there is no high voltage isolation required between the
phases. The cost of the DPFC system is lower than the UPFC. The DPFC has the
same control capability as the UPFC, which comprises the adjustment of the line
impedance, the transmission angle, and the bus voltage. Due to the high control
capability DPFC can also be used to improve the power quality and system
stability, such as low frequency power oscillation damping, voltage sag restoration
or balancing asymmetry.
KEYWORDS:
1.
AC–DC power
conversion
2.
Load flow
control
3.
Power
electronics
4.
Power
semiconductor devices
5.
Power system
control
6.
Power-transmission
control
SOFTWARE: MATLAB/SIMULINK
BLOCK
DIAGRAM:
Figure 1.DPFC configuration
EXPECTED
SIMULATION RESULTS:
Figure 2.Supply voltage during sag
condition
Figure 3. Injected voltage during
sag condition
Figure 4. Elimination of sag
voltage
Figure 5. Supply voltage during
swell
Figure 6. Injected voltage for
swell
Figure 7. Elimination of swell
voltage
CONCLUSION
The
series converter of the DPFC employs the DFACTS concept, which uses multiple
small single-phase converters instead of one large-size converter. It is proved
that the shunt and series converters in the DPFC can exchange active power at
the third-harmonic frequency, and the series converters are able to inject
controllable active and reactive power at the fundamental frequency. The DPFC
is also used to improving power quality problems such as sag and swell. The reliability
of the DPFC is greatly increased because of the redundancy of the series
converters. The total cost of the DPFC is also much lower than the UPFC,
because no high-voltage isolation is required at the series converter part and
the rating of the components of is low.
REFERENCES
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Divan and H. Johal, “Distributed facts-A new concept for realizing grid power
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compensator: Theory, modeling, and application”,IEEE Trans. Power Del., vol.
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[3] L.Gyugyi, C.D. Schauder, S. L.Williams, T. R.
Rietman, D. R. Torgerson, and A. Edris, “The unified power flow controller: A
new approach to power transmission control”, IEEE Trans. Power Del., vol. 10,
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[4] M. D. Deepak, E. B. William, S. S. Robert, K.
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static series compensator system for realizing active power flow control on
existing power lines”, IEEE Trans. Power Del., vol. 22, no. 1, pp. 642–649, Jan.2007.
[5] M.
Mohaddes, A. M. Gole, and S. Elez, “Steady state frequency response of
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