Mitigation of Power Quality Disturbances

Power Quality is a major concern of our modern industries and other consumers. Poor quality of supply
will affect the performance of customer equipment such as computers, microprocessors adjustable speed
drives, power electronic devices, life saving equipment in hospitals, etc. and result in heavy financial losses
to customers due to loss of production or breakdown in industries or loss of life in a hospital. The two
major power quality disturbances are voltage sag and harmonic distortion. In the event of voltage sag, due
to insufficient energy, equipments may malfunction or trip. Harmonics introduced by nonlinear loads can
pollute the input supply to the sensitive equipments and cause the connected equipments to malfunction. In
this work, a Power Quality Provider (QPP) is proposed and modeled by simulation.. The QPP has a novel
feature of performing dual functions of mitigation of sag and suppression of harmonics quickly,
dynamically and simultaneously using a simple unique and novel control scheme. The QPP will be
connected close the sensitive loads which are to be protected in the distribution network. For a case study
the hospital distribution network which supplies many life saving equipments such as MRI, CTSCAN,
computerized surgery equipment, etc. at Ipoh, Malaysia was chosen to conduct experiments. Experimental
results prove the credibility of QPP in mitigating power quality disturbances effectively, such that the
voltage at the sensitive loads are at the rated value and sinusoidal. The design, modeling and simulation are
done using PSS/ADEPT and PSCAD software.