ABSTRACT
Modern power utilities have to respond to a number
of challenges such as growth of electricity demand specially in non-linear
loads in power grids, consequently, some policies about the power with a higher
quality should be considered. In this paper, distributed power flow controller (DPFC)
which is similar to unified power flow controller (UPFC) in structure, is used
to mitigate the voltage sag and swell as a power quality issue. Unlike UPFC,
the common dc-link in DPFC, between the shunt and series converters is eliminated
and three-phase series converter is divided to several single-phase series
distributed converters through the transmission line. Also to detect the
voltage sags and determine the three single-phase reference voltages of DPFC,
the synchronous reference frame method is proposed. Application of DPFC in
power quality enhancement is simulated in Matlab/Simulink environment which
show the effectiveness of the proposed structure.
KEYWORDS:
1.
FACTS
2.
Power quality
3.
Sag and swell mitigation
4.
Distributed
power flow controller.
SOFTWARE: MATLAB/SIMULINK
CIRCUIT
DIAGRAM:
Fig.
1. The DPFC structure.
Fig.
2. Active power exchange between DPFC converters.
EXPECTED SIMULATION RESULTS:
Fig.
3. Three-phase load voltage sag waveform.
Fig.
4. Mitigation of three-phase load voltage sag with DPFC.
Fig.
5. Three-phase load current swell waveform.
Fig.
6. Mitigation of load current swell with DPFC.
CONCLUSION
The
power quality enhancement of the power transmission systems is an vital issue
in power industry. In this study, the application of DPFC as a new FACTS
device, in the voltage sag and swell mitigation of a system composed of a three-phase
source connected to a non-linear load through the parallel transmission lines
is simulated in Matlab/Simulink environment. The voltage dip is analyzed by
implementing a three-phase fault close to the system load. To detect the voltage
sags and determine the three single phase reference voltages of DPFC, the SRF
method is used as a detection and determination method. The obtained simulation
results show the effectiveness of DPFC in power quality enhancement, especially
in sag and swell mitigation.
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