Power quality improvement by using non-linear sliding mode controller with the dynamic voltage restorer
The essential issue of the power system network is power quality. The bus voltage must be maintained as a sinusoidal waveform. Many disturbances affect the supply voltage, such as notching, transients, voltage sag/swell. The major power quality problems are voltage sag/swell and harmonics, whi...
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| Main Author: | |
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| Format: | Thesis |
| Language: | English English English |
| Published: |
2021
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| Subjects: | |
| Online Access: | http://eprints.uthm.edu.my/4008/1/24p%20ALI%20BASIM%20MOHAMMED.pdf http://eprints.uthm.edu.my/4008/2/ALI%20BASIM%20MOHAMMED%20COPYRIGHT%20DECLARATION.pdf http://eprints.uthm.edu.my/4008/3/ALI%20BASIM%20MOHAMMED%20WATERMARK.pdf |
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| Summary: | The essential issue of the power system network is power quality. The bus voltage
must be maintained as a sinusoidal waveform. Many disturbances affect the supply
voltage, such as notching, transients, voltage sag/swell. The major power quality
problems are voltage sag/swell and harmonics, which cause tripping or malfunctioning
the equipment. The linear PID controller's output suffers from a high amplitude of
error when the input signals are noisy. This thesis gives an effective solution to protect
the sensitive loads from disturbances by utilizing the dynamic voltage restorer. It is
defined as a controlled voltage source connected in series between the sensitive loads
and the network through a series transformer to inject a proper voltage magnitude to
keep the sensitive loads at a constant value. The two non-linear controllers employ a
robust differentiator known as an approximate sliding mode differentiator (ACSMD)
with a non-linear sliding variable named a terminal PID sliding variable (TPIDSV) or
arctan PID sliding variable (ARTPIDSV). Simulation results were carried out by
MATLAB/Simulink to investigate the performance of the proposed controllers. The
performance improvement obtained from the proposed techniques upon comparison
with the case study as a linear PID controller, the steady-state error 85%-99%, the total
harmonic distortion 2%-51%, the voltage sag indices 85%-99% and the load voltage
magnitude 0.2%-8.7% for voltage sag and 0.08%-2.9% for voltage swell in all cases.
The results illustrated the DVR structure's ability to overcome the system's
disturbances, maintaining the voltage magnitude of the sensitive loads at a constant
value, minimizing the steady-state of error, and keeping the THD at an IEEE standard.
The DVR system performance is evaluated by utilizing three types of voltage sag
indices. |
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