A FACTS Device Distributed Power Flow
Controller (DPFC)
ABSTRACT:
This paper presents a new component within the
flexible ac-transmission system (FACTS) family, called distributed power-flow
controller (DPFC). The DPFC is derived from the unified
power-flow controller (UPFC). The DPFC can be
considered as a UPFC with an 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 employs the distributed FACTS (D-FACTS)
concept, which is to use multiple small-size single-phase converters instead of
the one 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.
Accordingly, 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. The principle and
analysis of the DPFC are presented in this paper and the corresponding
experimental results that are carried out on a scaled prototype are also shown.
KEYWORDS:
1.
AC–DC power
conversion
2.
Load flow
control
3.
Power
electronics
4.
Power
semiconductor devices
5.
Power-transmission
control.
SOFTWARE: MATLAB/SIMULINK
BLOCK
DIAGRAM:
Fig.
1. DPFC control block diagram.
CONCLUSION:
This
paper has presented a new concept called DPFC. The DPFC emerges from the UPFC
and inherits the control capability of the UPFC, which is the simultaneous
adjustment of the line impedance, the transmission angle, and the bus-voltage magnitude.
The common dc link between the shunt and series converters, which is used for
exchanging active power in the UPFC, is eliminated. This power is now
transmitted through the transmission line at the third-harmonic frequency. The series
converter of the DPFC employs the D-FACTS concept, which uses multiple small
single-phase converters instead of one large-size converter. 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. The DPFC concept has been verified by an
experimental setup. 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.
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[2]
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[3]
L.Gyugyi, C.D. Schauder, S. L.Williams, T. R. Rietman,D. R. Torgerson, andA.
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[4]
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