ABSTRACT
According to growth of electricity demand and the increased
number of non-linear loads in power grids, providing a high quality electrical
power should be considered. In this paper, voltage sag and swell of the power
quality issues are studied and distributed power flow controller (DPFC) is used
to mitigate the voltage deviation and improve power quality. The DPFC is a new
FACTS device, which its structure is similar to unified power flow controller
(UPFC). In spite of UPFC, in DPFC the common dc-link between the shunt and
series converters is eliminated and three-phase series converter is divided to
several single-phase series distributed converters through the line. The case
study contains a DPFC sited in a single-machine infinite bus power system
including two parallel transmission lines, which simulated in MATLAB/Simulink environment.
The presented simulation results validate the DPFC ability to improve the power
quality.
KEYWORDS:
1.
FACTS
2.
Power Quality
3.
Sag and Swell Mitigation
4.
Distributed Power Flow Controller
SOFTWARE: MATLAB/SIMULINK
BLOCK
DIAGRAM:
Fig. 1. The DPFC Structure
EXPECTED SIMULATION RESULTS:
Fig. 2. Three-phase load voltage
sag waveform
Fig. 3. Mitigation of three-phase
load voltage sag with DPFC
Fig. 4. Three-phase load current
swell waveform without DPFC
Fig. 5. Mitigation of three-phase
load current swell with DPFC
Fig. 6. Total harmonic distortion
of load voltage without DPFC
Fig. 7. Total harmonic distortion
of load voltage with DPFC
CONCLUSION
To
improve power quality in the power transmission system, there are some
effective methods. In this paper, the voltage sag and swell mitigation, using a
new FACTS device called distributed power flow controller (DPFC) is presented. The
DPFC structure is similar to unified power flow controller (UPFC) and has a
same control capability to balance the line parameters, i.e., line impedance,
transmission angle, and bus voltage magnitude. However, the DPFC offers some
advantages, in comparison with UPFC, such as high control capability, high
reliability, and low cost. The DPFC is modeled and three control loops, i.e.,
central controller, series control, and shunt control are design. The system
under study is a single machine infinite-bus system, with and without DPFC. To
simulate the dynamic performance, a three-phase fault is considered near the
load. It is shown that the DPFC gives an acceptable performance in power
quality mitigation and power flow control.
REFERENCES
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